AMERICAN INDUSTRIAL PROPERTIES REIT INC
8-K, 1998-01-20
REAL ESTATE INVESTMENT TRUSTS
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                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                        SECURITIES EXCHANGE ACT OF 1934



       Date of report (Date of earliest event reported): January 20, 1998



                      AMERICAN INDUSTRIAL PROPERTIES REIT
               (Exact Name of Registrant as Specified in Charter)


            TEXAS                         1-9016                 75-6335572
(State or Other Jurisdiction of      (Commission File         (I.R.S. Employer
Incorporation or Organization)            Number)         Identification Number)


             6210 N. Beltline Road, Suite 170, Irving, Texas 75063
              (Address of Principal Executive Offices) (Zip Code)


      Registrant's telephone number, including area code:  (972) 756-6000



                                 Not applicable
         (Former Name or Former Address, if Changed Since Last Report)
<PAGE>   2
ITEM 2.   ACQUISITION OR DISPOSITION OF ASSETS.

          On January 20, 1997, USAA Real Estate Income Investments I Limited
Partnership, A California Limited Partnership ("RELP I"), USAA Real Estate
Income Investments II Limited Partnership ("RELP II"), USAA Income Properties
III Limited Partnership ("RELP III") and USAA Income Properties IV Limited
Partnership ("RELP IV") (collectively, the "Partnerships") merged with and into
American Industrial Properties REIT (the "Trust"), the Registrant, pursuant to
Amended and Restated Agreements and Plans of Merger dated as of June 30, 1997
(the "Merger Agreement"), previously filed as Annex I to the Joint Proxy
Statement/Prospectus of the Trust and the Partnerships that was a made a part
of the Registration Statement on Form S-4 (File No. 333-31823) filed with the
Securities and Exchange Commission on July 22, 1997, and as subsequently
amended.  As provided in the Merger Agreement, each Unit in RELP I was
converted into the right to receive 15.90 common shares of beneficial interest
of the Trust ("Shares"), each Unit in RELP II was be converted into the right
to receive 28.63 Shares, each Unit in RELP III  was converted into the right to
receive 16.60 Shares and each Unit in RELP IV was  converted into the right to
receive 15.14 Shares.  The Trust issued approximately 4,412,829 Shares in
exchange for the Units.  The closing price of the Trust's Shares on January 20,
1998 was $______.

          The Partnerships owned, either directly or through a joint venture,
interests in properties containing in the aggregate 1,402,000 net rentable
square feet.  Excluding any properties that were not transferred in connection
with the Merger, each of the Partnerships held the following properties: (i)
RELP I held one office building in San Diego and one retail shopping center in
Daytona Beach, Florida; (ii) RELP II held a manufacturing and distribution
facility located in Elk Grove Village, Illinois and one industrial warehouse
building in Lakeland, Florida; (iii) RELP III held one office building complex
in Manhattan Beach, California and one office building complex in Phoenix,
Arizona; (iv) RELP IV held one industrial building in Milpitas, California, one
industrial building in San Diego, California, one office building in St. Louis,
Missouri, and a joint venture interest in the sole beneficiary of a trust which
owns an office/research and development facility in Chelmsford, Massachusetts.
An affiliate of USAA Real Estate Company (an affiliate of the Partnerships)
will manage and lease the former Partnership properties on behalf of the Trust
after the merger.

          Effective with the merger, the Trust will have a portfolio (owned or
controlled) of net leasable square feet totaling 4,315,000, located in 10
states.

ITEM 7.   FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

(a)       FINANCIAL STATEMENTS OF BUSINESS ACQUIRED.

          Financial statements for the Partnerships will be filed within 60
days from the date this report is filed.





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(b)       PRO FORMA FINANCIAL INFORMATION.

          Pro forma financial information will be filed within 60 days from the
date this report is filed.

(c)       EXHIBITS.

<TABLE>
<S>       <C>
*2.1      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Real Estate Income Investments I, A California Limited Partnership.

*2.2      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Real Estate Income Investments II Limited Partnership.


*2.3      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Income Properties III Limited Partnership.

*2.4      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Income Properties IV Limited Partnership.
</TABLE>



- --------------------
* Filed herewith.





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                                   SIGNATURES


          Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has  duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.


                                        AMERICAN INDUSTRIAL PROPERTIES REIT



                                           /s/ Charles W. Wolcott             
                                        --------------------------------------
                                           Charles W. Wolcott
                                           President and Chief Executive Officer

Dated: January 20, 1998





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<PAGE>   5
                                  EXHIBIT LIST


<TABLE>
<S>       <C>
*2.1      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Real Estate Income Investments I, A California Limited Partnership.

*2.2      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Real Estate Income Investments II Limited Partnership.


*2.3      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Income Properties III Limited Partnership.

*2.4      Amended and Restated Agreement and Plan of Merger dated as of June 30, 1997, by and between American
          Industrial Properties REIT and USAA Income Properties IV Limited Partnership.
</TABLE>

- ----------------------
* Filed herewith

<PAGE>   1


                                                                     EXHIBIT 2.1

                              AMENDED AND RESTATED
                          AGREEMENT AND PLAN OF MERGER


         THIS AMENDED AND RESTATED AGREEMENT AND PLAN OF MERGER (this
"Agreement"), dated as of June 30, 1997, is entered into by and between
American Industrial Properties REIT, a Texas real estate investment trust
("AIP") , and USAA Real Estate Income Investments I, A California Limited
Partnership, a California limited partnership ("RELP").  USAA Real Estate
Company, a Delaware corporation ("Realco"), is a party to this Agreement solely
for the purpose of binding itself to the provisions of Section 7.10 hereunder.

                                    RECITALS

         A.      The Board of Trust Managers of AIP (the "Board of Trust
Managers") and the general partner of RELP have each determined that a business
combination between AIP and RELP is in the best interests of their shareholders
and partners, respectively, and presents an opportunity for their respective
businesses to achieve strategic and financial benefits, and accordingly have
agreed to effect a merger subject to the terms and conditions set forth herein.

         B.      AIP and RELP desire to make certain representations,
warranties and agreements in connection with the merger.

         NOW, THEREFORE, in consideration of the foregoing, and of the
representations, warranties, covenants and agreements contained herein, AIP and
RELP hereby agree as follows:

                             ARTICLE I.  THE MERGER

         1.1.    The Merger. Subject to the terms and conditions of this
Agreement, at the Effective Time (as defined in Section 1.3), RELP shall be
merged with and into AIP in accordance with this Agreement and the Plan of
Merger (the "Plan of Merger") in substantially the form attached hereto as
Exhibit A, with such completions, additions and substitutions conforming to the
terms of this Agreement as the parties shall approve, such approval to be
conclusively evidenced by their causing the Plan of Merger containing such
completions, additions or substitutions to be filed in accordance with
applicable laws; and the separate existence of RELP shall thereupon cease (the
"Merger"). AIP shall be the surviving entity in the Merger (sometimes
hereinafter referred to as the "Survivor").  The Merger shall have the effects
specified in Section 23.60  of the Texas Real Estate Investment Trust Act, as
amended (the "Texas REIT Act") and Section 15678.6 of the California Revised
Limited Partnership Act (the "LP Act").

         1.2.    The Closing. Subject to the terms and conditions of this
Agreement, the closing of the Merger (the "Closing") shall take place at the
offices of Liddell, Sapp, Zivley, Hill & LaBoon, L.L.P. ("Liddell, Sapp"),
located at 2200 Ross Avenue, Suite 900, Dallas, Texas at 10:00 a.m., local
time, within five business days after receipt of approval of the Merger by
AIP's shareholders and RELP's partners, or at such other time, date or place as
AIP and RELP may agree. The date on which the Closing occurs is hereinafter
referred to as the "Closing Date."
<PAGE>   2
         1.3.    Effective Time. If all the conditions to the Merger set forth
in Article VIII shall have been fulfilled or waived (and this Agreement shall
not have been terminated as provided in Article IX), AIP and RELP shall cause
Articles of Merger satisfying the requirements of the Texas REIT Act and
Articles of Merger satisfying the requirements of the LP Act to be properly
executed, verified and delivered for filing in accordance with the LP Act and
the Texas REIT Act on the Closing Date. The Merger shall become effective for
accounting and all other purposes to the fullest extent permitted by law as of
the close of business on December 31, 1997 (the "Effective Time") or such other
date as may be agreed to by the parties. For state law purposes, the Merger
shall become effective upon the issuance of a certificate of merger by the
Secretary of State of the State of California in accordance with the LP Act or
at such later time which AIP and RELP shall have agreed upon and designated in
such filings in accordance with applicable law.

                       ARTICLE II.  DECLARATION OF TRUST
                           AND BYLAWS OF THE SURVIVOR

         2.1.    Declaration of Trust.  The Declaration of Trust of AIP  in
effect immediately prior to the Effective Time shall be the Declaration of
Trust of the Survivor until duly amended in accordance with applicable law.

         2.2.    Bylaws.  The Bylaws of AIP in effect immediately prior to the
Effective Time shall be the Bylaws of the Survivor until duly amended in
accordance with applicable law.

                ARTICLE III.  TRUST MANAGERS AND OFFICERS OF AIP

         3.1.    Trust Managers.  The Trust Managers of AIP immediately prior
to the Effective Time shall be the Trust Managers of AIP as of the Effective
Time.

         3.2.    Officers.  The officers of AIP immediately prior to the
Effective Time shall be the officers of AIP as of the Effective Time.

                    ARTICLE IV.  RELP PARTNERSHIP  INTERESTS

         4.1.    Conversion of the RELP Partnership Interest.  (a)   At the
Effective Time, each Common Share of Beneficial Interest of AIP outstanding
immediately prior to the Effective Time shall remain outstanding and shall
represent one Common Share of Beneficial Interest of AIP.

         (b)     At the Effective Time, the general and limited partnership
interests of RELP  (each a  "RELP Interest"), issued and outstanding
immediately prior to the Effective Time shall, by virtue of the Merger and
without any action on the part of holder thereof, be converted into the right
to receive Common Shares of Beneficial Interest, $0.10 par value per share (the
"AIP Common Shares"), of AIP.  The aggregate number of AIP Common Shares to be
issued to the RELP partners in connection with the Merger shall be equal to
$11,400,000 (the "Purchase Price") divided by the Share Price (the "Total
Shares").  If, during the period from the date hereof to and including the
Closing Date, (i) the RELP pays any mortgage indebtedness existing on the date
hereof or (ii) the outstanding AIP Common Shares shall have been changed to a
different number of shares by reason of any share dividend, subdivision,
reclassification, recapitalization, share split, reverse share split,

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combination, exchange of shares or the like, the Purchase Price shall be
appropriately adjusted.  The term "Share Price" shall mean $2.625.  The number
of AIP Common Shares to be received by a partner shall be equal to the Total
Shares multiplied by such partner's percentage interest in RELP plus each
limited partner's pro rata portion of the general partnership interest of the
RELP's general partner.

         (c)     As a result of the Merger and without any action on the part
of the holder thereof, at the Effective Time,  all RELP Interests  shall cease
to be outstanding and shall be canceled and retired, and each holder of a RELP
Interest shall thereafter cease to have any rights with respect to such RELP
Interest, except the right to receive, without interest, the AIP Common Shares
and cash for fractional shares of AIP Common Shares in accordance with Sections
4.1(b) and 4.2(e).

         4.2.    Exchange of RELP Interests.  (a)  As of the Effective Time,
AIP shall deposit, or shall cause to be deposited, with an exchange agent
selected by AIP, which shall be AIP's Transfer Agent or such other party
reasonably satisfactory to RELP (the "Exchange Agent"), for the benefit of the
holders of RELP Interests, for exchange in accordance with this Article IV,
certificates representing the Total Shares and the cash in lieu of fractional
shares (such cash and certificates for the Total Shares together with any
dividends or distributions with respect thereto, being hereinafter referred to
as the "Exchange Fund") to be issued pursuant to Section 4.1 and paid pursuant
to this Section 4.2 in exchange for outstanding RELP Interests.

         (b)     Promptly after the Effective Time, AIP shall cause the
Exchange Agent to mail to each holder of record of a RELP Interest (x) a
certificate representing the number of whole shares of AIP Common Shares and
(y) a check representing the amount of cash in lieu of fractional shares, if
any, and unpaid dividends and distributions, if any, which such holder has the
right to receive in respect of the RELP Interest surrendered pursuant to the
provisions of this Article IV, after giving effect to any required withholding
tax.  No interest will be paid or accrued on the cash in lieu of fractional
shares and unpaid dividends and distributions, if any, payable to holders of
RELP Interests.  In the event of a transfer of ownership of RELP Interests
which is not registered in the transfer records of RELP, a certificate
representing the proper number of AIP Common Shares, together with a check for
the cash to be paid in lieu of fractional shares, may be issued to such a
transferee if such holder presents to the Exchange Agent, all documents
required to evidence and effect such transfer and to evidence that any
applicable transfer taxes have been paid.

         (c)     At and after the Effective Time, there shall be no transfers
on the transfer books of RELP of RELP Interests which were outstanding
immediately prior to the Effective Time.

         (d)     No fractional AIP Common Shares shall be issued pursuant
hereto. In lieu of the issuance of any fractional AIP Common Shares pursuant to
Section 4.1(b), cash adjustments will be paid to holders in respect of any
fractional AIP Common Shares that would otherwise be issuable, and the amount
of such cash adjustment shall be equal to such fractional proportion of the
Share Price.

         (e)     Any portion of the Exchange Fund (including the proceeds of
any investments thereof and any AIP Common Shares) that remains unclaimed by
the former partners of RELP one year after the Effective Time shall be
delivered to AIP. Any former partners of RELP who have not theretofore





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<PAGE>   4
complied with this Article IV shall thereafter look only to AIP for delivery of
their AIP Common Shares, and payment of cash in lieu of fractional shares and
unpaid dividends and distributions on the AIP Common Shares deliverable in
respect of each RELP Interest such partners hold as determined pursuant to this
Agreement, in each case, without any interest thereon.

         (f)     None of AIP, RELP, the Exchange Agent or any other person
shall be liable to any former holder of RELP Interests for any amount properly
delivered to a public official pursuant to applicable abandoned property,
escheat or similar laws.


               ARTICLE V.  REPRESENTATIONS AND WARRANTIES OF RELP

         RELP represents and warrants to AIP as set forth below. As
contemplated below, a "RELP Disclosure Letter" will be delivered to AIP on or
before September 20, 1997.  The RELP Disclosure Letter shall provide the
information or exceptions described below and shall list all of the assets of
the RELP that will not be transferred in connection with the Merger. The RELP
Disclosure Letter shall be amended prior to Closing to cause such
representations and warranties to be materially true and correct on the Closing
Date, but RELP shall remain liable for any material breach of such
representations and warranties reflected in such amendment only as provided in
Section 9.5(d), below.

         5.1.    Existence; Good Standing; Authority; Compliance with Law.  (a)
RELP is a limited partnership,  duly formed, validly existing and in good
standing under the laws of the State of California.  To its actual knowledge,
RELP is duly licensed or qualified to do business as a foreign limited
partnership and is in good standing under the laws of any other state of the
United States in which the character of the properties owned or leased by it
therein or in which the transaction of its business makes such qualification
necessary, except where the failure to be so qualified would not have a
material adverse effect on the business, results of operations or financial
condition of RELP (a "RELP Material Adverse Effect"). RELP has all requisite
power and authority to own, operate, lease and encumber its properties and
carry on its business as now conducted.

         (b)     To the RELP's actual knowledge, it is not in violation of any
order of any court, governmental authority or arbitration board or tribunal, or
any law, ordinance, governmental rule or regulation to which RELP or any of its
properties or assets is subject, where such violation would have a RELP
Material Adverse Effect. RELP has obtained all licenses, permits and other
authorizations and has taken all actions required by applicable law or
governmental regulations in connection with its business as now conducted,
where the failure to obtain any such item or to take any such action would have
a RELP Material Adverse Effect. A copy of RELP's Agreement of Limited
Partnership and Certificate of Limited Partnership (collectively, the "RELP
Organizational Documents") have been delivered or made available to AIP and its
counsel and such documents will be listed in the RELP Disclosure Letter and
were or will be true and correct when delivered or made available.

         5.2.    Authorization, Validity and Effect of Agreements.  RELP has
the requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions





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contemplated by this Agreement (the "RELP Ancillary Agreements"). Subject only
to the approval of this Agreement and the transactions contemplated hereby in
accordance with the Agreement of Limited Partnership of the RELP, the
consummation by RELP of this Agreement, the RELP Ancillary Agreements and the
transactions contemplated hereby have been duly authorized by all requisite
action on the part of RELP. In reliance upon the legal opinion described in
Section 8.2(e), RELP believes this Agreement constitutes, and the RELP
Ancillary Agreements (when executed and delivered pursuant hereto for value
received) will constitute, the valid and legally binding obligations of RELP,
enforceable against RELP in accordance with their respective terms, subject to
applicable bankruptcy, insolvency, moratorium or other similar laws relating to
creditors' rights and general principles of equity (collectively, "Equitable
Remedies").

         5.3.    Future Issuances.  To RELP's actual knowledge, there are not
at the date of this Agreement any existing options, warrants, calls,
subscriptions, convertible securities, or other rights, agreements or
commitments which obligate RELP to issue, transfer or sell any RELP Interests.
After the Effective Time, AIP will have no obligation to issue, transfer or
sell any RELP Interest.

         5.4.    Other Interests.  Except as set forth in the RELP Disclosure
Letter, RELP does not own directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

         5.5.    No Violation.  To RELP's actual knowledge, neither the
execution and delivery by RELP of this Agreement nor the consummation by RELP
of the transactions contemplated hereby in accordance with the terms hereof,
will: (i) conflict with or result in a breach of any provisions of the
Agreement of Limited Partnership of RELP; (ii) except as contemplated by the
RELP Ancillary Agreements or as will be set forth in the RELP Disclosure
Letter, violate, or conflict with, or result in a breach of any provision of,
or constitute a default (or an event which, with notice or lapse of time or
both, would constitute a default) under, or result in the termination or in a
right of termination or cancellation of, or accelerate the performance required
by, or result in the creation of any lien, security interest, charge or
encumbrance upon any of the properties of RELP under, or result in being
declared void, voidable or without further binding effect, any of the terms,
conditions or provisions of any note, bond, mortgage, indenture, deed of trust
or any license, franchise, permit, lease, contract, agreement or other
instrument, commitment or obligation to which RELP is a party, or by which RELP
or any of its  properties is bound or affected, except for any of the foregoing
matters which, individually or in the aggregate, would not have a RELP Material
Adverse Effect; or (iii) other than the filings provided for in Article I, any
filings required under the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), the Securities Act or applicable state securities and "Blue
Sky" laws (collectively, the "Regulatory Filings"), require any consent,
approval or authorization of, or declaration, filing or registration with, any
domestic governmental or regulatory authority, except where the failure to
obtain any such consent, approval or authorization of, or declaration, filing
or registration with, any governmental or regulatory authority would not have
an RELP Material Adverse Effect.

         5.6.    SEC Documents.  (a) RELP has made available or will make
available to AIP prior to September 30, 1997, each registration statement,
report, proxy statement or information statement and all exhibits thereto
prepared by it or relating to its properties (including registration statements





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<PAGE>   6
covering mortgage pass-through certificates) since January 1, 1994, each in the
form (including exhibits and any amendments thereto) filed with the SEC
(collectively, the "RELP Reports"). The RELP Reports, which were or will be
filed with the SEC in a timely manner, constitute all forms, reports and
documents required to be filed by RELP under the Securities Act of 1933, as
amended (the "Securities Act"), the Exchange Act and the rules and regulations
promulgated thereunder (collectively the "Securities Laws") for the periods
stated above.

         (b)     To the RELP's actual knowledge, as of their respective dates,
the RELP Reports (i) complied as to form in all material respects with the
applicable requirements of the Securities Laws and (ii) did not contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements made therein, in the
light of the circumstances under which they were made, not misleading. To the
RELP's actual knowledge, each of the balance sheets of RELP included in or
incorporated by reference into the RELP Reports (including the related notes
and schedules) fairly presents the financial position of RELP as of its date
and each of the consolidated statements of income, retained earnings and cash
flows of RELP included in or incorporated by reference into the RELP Reports
(including any related notes and schedules) fairly presents the results of
operations, retained earnings and cash flows, as the case may be, of RELP for
the periods set forth therein (subject, in the case of unaudited statements, to
normal year-end audit adjustments which would not be material in amount or
effect), in each case in accordance with generally accepted accounting
principles consistently applied during the periods involved, except as may be
noted therein and except, in the case of the unaudited statements, as permitted
by the Securities Laws.


         (c)     Except as and to the extent set forth on the balance sheet of
RELP at March 31, 1997, including all notes thereto, or as set forth in the
RELP Reports, RELP has no material liabilities or obligations of any nature
(whether accrued, absolute, contingent or otherwise) that would be required to
be reflected on, or reserved against in, a balance sheet of RELP or in the
notes thereto, prepared in accordance with generally accepted accounting
principles consistently applied, except liabilities arising in the ordinary
course of business since such date which would not have a RELP Material Adverse
Effect.

         5.7.    Litigation.  To the RELP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which RELP is a party or by which any of its
properties or assets are bound or to which USAA Investors I, Inc. (the "General
Partner")  or the General Partner's,  directors, officers, or affiliates is a
party or by which any of their properties or assets are bound, and (ii) except
as will be set forth in the RELP Disclosure Letter, no actions, suits or
proceedings pending against RELP or against the General Partner or the General
Partner's directors, officers or affiliates or, to the knowledge of the General
Partner, threatened against RELP or against the General Partner or the General
Partner's  directors, officers  or affiliates, at law or in equity, or before
or by any federal or state commission, board, bureau, agency or
instrumentality, that in the case of clauses (i) or (ii) above are reasonably
likely, individually or in the aggregate, to have a RELP Material Adverse
Effect.

         5.8.    Absence of Certain Changes.  Except as disclosed in the RELP
Reports filed prior to the date hereof, since March 31, 1997, (i) RELP
conducted its business only in the ordinary course of such business (which for
purposes of this section only, shall include all acquisitions of real estate





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<PAGE>   7
properties and financing arrangements made in connection therewith or otherwise
will be set forth in the RELP Disclosure Letter); (ii) there has not been any
RELP Material Adverse Effect; (iii) there has not been any distribution,
setting aside or payment of any distribution with respect to any RELP Interest,
and (iv) there has not been any material change in RELP's accounting
principles, practices or methods.

         5.9.    Taxes.  (a)  Except as may be set forth in the RELP Disclosure
Letter, RELP (i) has timely filed all federal, state and foreign tax returns
including, without limitation, information returns and reports required to be
filed by it for tax periods ended prior to the date of this Agreement or
requests for extensions have been timely filed and any such request has been
granted and has not expired and all such returns are accurate and complete in
all material respects, (ii) has paid or accrued all taxes shown to be due and
payable on such returns or which have become due and payable pursuant to any
assessment, deficiency notice, 30-day letter or other notice received by it and
(iii) has properly accrued all taxes for such periods and periods subsequent to
the periods covered by such returns. RELP has not received notice that the
federal, state and local income and franchise tax returns of RELP has been or
will be examined by any taxing authority. RELP has not executed or filed with
the Internal Revenue Service (the "IRS") or any other taxing authority any
agreement now in effect extending the period for assessment or collection of
any income or other taxes.

         (b)     Except as may be set forth in the RELP Disclosure Letter, RELP
is not  a party to any pending action or proceeding by any governmental
authority for assessment or collection of taxes, and no claim for assessment or
collection of taxes has been asserted against it. True, correct and complete
copies of all federal, state and local income or franchise tax returns filed by
RELP since January 1, 1991 and all communications relating thereto have been
delivered to AIP or made available to representatives of AIP or will be so
delivered or made available prior to September 30, 1997. RELP does not hold any
asset (i) the disposition of which could be subject to rules similar to Section
1374 of the Internal Revenue Code of 1986, as amended (the "Code") as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 5.9, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

         5.10.   Books and Records.  The books of account and other financial
records of RELP are in all material respects true, complete and correct, have
been maintained in accordance with good business practices, and are accurately
reflected in all material respects in the financial statements included in the
RELP Reports.

         5.11.   Properties.  (a)  RELP owns fee simple title to each of the
real properties reflected on the most recent balance sheet of RELP included in
the RELP Reports or as may be identified in the RELP Disclosure Letter (the
"RELP Properties"), which are all of the real estate properties owned by it,
free and clear of liens, mortgages or deeds of trust, claims against title,
charges which are liens or security interests ("Encumbrances") except as will
be noted in the RELP Disclosure Letter. To RELP's actual knowledge, the RELP
Properties are not subject to any rights of way, written agreements, laws,
ordinances and regulations affecting building use or occupancy, or reservations
of an interest in title (collectively, "Property Restrictions"), except for (i)
Encumbrances and Property Restrictions that will be set forth in the RELP
Disclosure Letter, (ii) Property Restrictions imposed or promulgated by law or
any governmental body or authority with respect to real property, including





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<PAGE>   8
zoning regulations, provided they do not materially adversely affect the
current use of the property, (iii) Encumbrances and Property Restrictions
disclosed on existing title reports or current surveys (in either case copies
of which title reports and surveys have been or will be delivered or made
available to AIP September 30, 1997), (iv) mechanics', carriers', workmen's,
repairmen's liens and other Encumbrances, Property Restrictions and other
limitations of any kind, if any, which have heretofore been bonded (and that
will be listed in the RELP Disclosure Letter) or which individually or in the
aggregate do not exceed $100,000, do not materially detract from the value of
or materially interfere with the present use of any of the RELP Properties
subject thereto or affected thereby, and do not otherwise materially impair
business operations conducted by RELP and which have arisen or been incurred
only in its construction activities or in the ordinary course of business.

         (b)     Valid policies of title insurance have been issued insuring
either (a) RELP's fee simple title to the RELP Properties or (b) first mortgage
liens thereon, subject only to the matters disclosed above and as may be set
forth in the RELP Disclosure Letter, and such policies are, at the date hereof,
in full force and effect and no claim has been made against any such policy. To
RELP's actual knowledge, except as will be set forth in the RELP Disclosure
Letter: (i) there is no certificate, permit or license from any governmental
authority having jurisdiction over any of the RELP Properties or any agreement,
easement or other right which is necessary to permit the lawful use and
operation of the buildings and improvements on any of the RELP Properties or
which is necessary to permit the lawful use and operation of all driveways,
roads and other means of egress and ingress to and from any of the RELP
Properties that has not been obtained and is not in full force and effect, or
of any pending threat of modification or cancellation of any of same; (ii) RELP
has not received written notice of any material violation of any federal, state
or municipal law, ordinance, order, regulation or requirement affecting any
portion of any of the RELP Properties issued by any governmental authority;
(iii) there are no structural defects relating to the RELP Properties and no
RELP Properties whose building systems are not in working order in any material
respect; and (iv) there is (A) no physical damage to any RELP Property in
excess of $100,000 for which there is no insurance in effect covering the cost
of the restoration, (B) no current renovation to any RELP Property the cost of
which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any RELP Property, the cost of which exceeds $100,000.

         (c)     Except as will be set forth in the RELP Disclosure Letter,
RELP has not received notice to the effect that and there are no (A)
condemnation or rezoning proceedings that are pending or threatened with
respect to any of the RELP Properties or (B) zoning, building or similar laws,
codes, ordinances, orders or regulations that are or will be violated by the
continued maintenance, operation or use of any buildings or other improvements
on any of the RELP Properties or by the continued maintenance, operation or use
of the parking areas. All work to be performed, payments to be made and actions
to be taken by RELP prior to the date hereof pursuant to any agreement entered
into with a governmental body or authority in connection with a site approval,
zoning reclassification or other similar action relating to the RELP Properties
(e.g., Local Improvement District, Road Improvement District, Environmental
Mitigation) has been performed, paid or taken, as the case may be, and RELP is
not aware of any planned or proposed work, payments or actions that may be
required after the date hereof pursuant to such agreements, except as will be
set forth in the RELP Disclosure Letter.





                                       8
<PAGE>   9
         5.12.   Environmental Matters.  To RELP's actual knowledge, RELP has
not  caused (i) the unlawful presence of any hazardous substances, hazardous
materials, toxic substances or waste materials (collectively, "Hazardous
Materials") on any of the RELP Properties, or (ii) any unlawful spills,
releases, discharges or disposal of Hazardous Materials to have occurred or be
presently occurring on or from the RELP Properties as a result of any
construction on or operation and use of such properties, which presence or
occurrence would, individually or in the aggregate, have a RELP Material
Adverse Effect; and in connection with the construction on or operation and use
of the RELP Properties, RELP has not failed to comply, in any material respect,
with any applicable local, state and federal environmental laws, regulations,
ordinances and administrative and judicial orders relating to the generation,
recycling, reuse, sale, storage, handling, transport and disposal of any
Hazardous Materials.

         5.13.   Labor Matters.  RELP is not a party to, or bound by, any
collective bargaining agreement, contract or other agreement or understanding
with a labor union or labor union organization. There is no unfair labor
practice or labor arbitration proceeding pending or, to the knowledge of the
General Partner, threatened against RELP relating to its business, except for
any such proceeding which would not have a RELP Material Adverse Effect. To the
knowledge of the General Partner, there are no organizational efforts with
respect to the formation of a collective bargaining unit presently being made
or threatened involving employees of RELP or any of its Subsidiaries.

         5.14.   No Brokers.  Except the fee that is to be paid to Houlihan
Lokey Howard & Zukin ("Houlihan")  by RELP as described in Section 5.15 below,
RELP has not entered into any contract, arrangement or understanding with any
person or firm which may result in the obligation of RELP or AIP to pay any
finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby. RELP is not aware of any claim for
payment of any finder's fees, brokerage or agent's commissions or other like
payments in connection with the negotiations leading to this Agreement or the
consummation of the transactions contemplated hereby.

         5.15.   Opinion of Financial Advisor.  RELP has retained Houlihan to
review the transaction contemplated by this Agreement and to issue an opinion
to the effect that, as of the date of such opinion, the Purchase Price is fair
to the holders of RELP Interests from a financial point of view.

         5.16.   Related Party Transactions.  Except as set forth in the RELP
Disclosure Letter, there are no arrangements, agreements or contracts entered
into by RELP with (i) any consultant, (ii) any person who is an officer,
director or affiliate of RELP or its General Partner, any relative of any of
the foregoing or any entity of which any of the foregoing is an affiliate, or
(iii) any person who acquired RELP Interests in a private placement.

         5.17.   Contracts and Commitments.  The RELP Disclosure Letter will
set forth (i) all unsecured notes or other obligations of RELP which
individually may result in total payments in excess of $100,000, (ii) all
notes, debentures, bonds and other evidence of indebtedness which are secured
or collateralized by mortgages, deeds of trust or other security interests in
the RELP Properties or personal property of RELP,  and (iii) each commitment
entered into by RELP which may result in total payments or liability in excess
of $100,000. Copies of the foregoing will be





                                       9
<PAGE>   10
delivered or made available to AIP prior to September 30, 1997, will be listed
on the RELP Disclosure Letter and will be materially true and correct when
delivered or made available. RELP has not received any notice of a default that
has not been cured under any of the documents described in clause (i) above or
is in default respecting any payment obligations thereunder beyond any
applicable grace periods. All options of RELP to purchase real property will be
set forth on the RELP Disclosure Letter and such options and RELP's rights
thereunder are in full force and effect. All joint venture agreements to which
RELP is a party will be set forth on the RELP Disclosure Letter and RELP is not
in default with respect to any obligations, which individually or in the
aggregate are material, thereunder.

         5.18.    Development Rights.  Set forth in the RELP Disclosure Letter
will be a list of all material agreements entered into by RELP relating to the
development, rehabilitation, capital improvement or construction of office
buildings, industrial facilities  or other real estate properties, which
development or construction has not been substantially completed as of the date
of this Agreement. Such agreements, true and correct copies of all of which
will be delivered or made available to AIP prior to September 30, 1997, will be
listed in the RELP Disclosure Letter, have not been modified and are valid and
binding in accordance with their respective terms.

         5.19.    Convertible Securities.  To RELP's actual knowledge, RELP has
no outstanding options, warrants or other securities exercisable for, or
convertible into, RELP Interests, the terms of which would require any anti-
dilution adjustments by reason of the consummation of the transactions
contemplated hereby.

              ARTICLE VI .  REPRESENTATIONS AND WARRANTIES OF AIP

         AIP represents and warrants to RELP as set forth below.  As
contemplated below, an "AIP Disclosure Letter" will be delivered to RELP on or
before September 20, 1997.  The AIP Disclosure Letter shall provide the
information or exceptions described below. The AIP Disclosure Letter shall be
amended prior to Closing to cause such representations and warranties to be
materially true and correct on the Closing Date, but AIP shall remain liable
for any material breach of such representations and warranties reflected in
such amendment only as provided in Section 9.5(d), below.

         6.1.     Existence; Good Standing; Authority; Compliance with Law.
(a)  AIP is a real estate investment trust duly organized and  validly existing
under the laws of the State of Texas.   To AIP's actual knowledge, AIP is duly
licensed or qualified to do business and is in good standing under the laws of
any other state of the United States in which the character of the properties
owned or leased by it therein or in which the transaction of its business makes
such qualification necessary, except where the failure to be so qualified would
not have a material adverse effect on the business, results of operations or
financial condition of AIP and its subsidiaries taken as a whole (an "AIP
Material Adverse Effect"). AIP has all requisite power and authority to own,
operate, lease and encumber its properties and carry on its business as now
conducted. Each of AIP's Subsidiaries is a corporation,





                                       10
<PAGE>   11
limited liability company or partnership duly organized, validly existing and
in good standing under the laws of its jurisdiction of incorporation or
organization, has the requisite power and authority to own its properties and
to carry on its business as it is now being conducted, and is duly qualified to
do business and is in good standing in each jurisdiction in which the ownership
of its property or the conduct of its business requires such qualification,
except for jurisdictions in which such failure to be so qualified or to be in
good standing would not have an AIP Material Adverse Effect.

         (b)     To AIP's actual acknowledge, neither AIP nor any AIP
Subsidiary is in violation of any order of any court, governmental authority or
arbitration board or tribunal, or any law, ordinance, governmental rule or
regulation to which AIP or any AIP Subsidiary or any of their respective
properties or assets is subject, where such violation would have an AIP
Material Adverse Effect. AIP and its Subsidiaries have obtained all licenses,
permits and other authorizations and have taken all actions required by
applicable law or governmental regulations in connection with their business as
now conducted, where the failure to obtain any such item or to take any such
action would have an AIP Material Adverse Effect. Copies of AIP's and its
Subsidiaries' Declaration of Trust, Articles of Incorporation, Bylaws,
organizational documents and partnership and joint venture agreements have been
or will be prior to September 30, 1997, delivered or made available to RELP and
such documents will be listed in the AIP Disclosure Letter and were or will be
true and correct when delivered or made available. For the purposes of the
immediately preceding sentence, the term "Subsidiary"shall include the entities
set forth in the AIP Disclosure Letter, which are all of AIP's Subsidiaries.

         6.2.    Authorization, Validity and Effect of Agreements.  AIP has
the requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions contemplated by this
Agreement to which it is a party (the "AIP Ancillary Agreements"). Subject only
to the approval of the issuance of AIP Common Shares pursuant to the Merger
contemplated hereby by the holders of two-thirds of the outstanding AIP Common
Shares, present and voting thereon, the consummation by AIP of this Agreement,
the AIP Ancillary Agreements and the transactions contemplated hereby have been
duly authorized by all requisite action on the part of AIP. This Agreement
constitutes, and the AIP Ancillary Agreements (when executed and delivered
pursuant hereto for value received) will constitute, the valid and legally
binding obligations of AIP enforceable against AIP in accordance with their
respective terms, subject to Equitable Remedies.

         6.3.    Capitalization.  On June 15, 1997, the authorized capital
stock of AIP consists of 10,000,000 Common Shares. As of the date hereof, all
10,000,000 Common Shares are outstanding. AIP has no outstanding bonds,
debentures, notes or other obligations (other than to Realco), the holders of
which have the right to vote (or which are convertible into or exercisable for
securities having the right to vote) with the shareholders of AIP on any
matter. Except as set forth in the AIP Disclosure Letter, all such issued and
outstanding of AIP Common Shares are duly authorized, validly issued, fully
paid, nonassessable and free of preemptive rights. Except as set forth in the
AIP Disclosure Letter, there are not at the date of this Agreement any existing
options, warrants, calls,





                                       11
<PAGE>   12
subscriptions, convertible securities, or other rights, agreements or
commitments which obligate AIP or any of its Subsidiaries to issue, transfer or
sell any shares or other equity interest of AIP or any of its Subsidiaries
except under any employee incentive plan approved by AIP's shareholders. There
are no agreements or understandings to which AIP is a party with respect to the
voting of any AIP Common Shares or which restrict the transfer of any such
shares, except in order to protect its REIT status.

         6.4.    Subsidiaries.  Except as set forth in the AIP Disclosure
Letter, AIP owns directly or indirectly each of the outstanding shares of
capital stock or all of the partnership or other equity interests of each of
AIP's Subsidiaries free and clear of all liens, pledges, security interests,
claims or other encumbrances other than liens imposed by local law which are
not material.

         6.5.    Other Interests.   Except as will be disclosed in the AIP
Disclosure Letter and except for interests in the AIP Subsidiaries, neither AIP
nor any AIP Subsidiary owns directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

         6.6.    No Violation.   Neither the execution and delivery by AIP of
this Agreement nor the consummation by AIP of the transactions contemplated
hereby in accordance with the terms hereof, will: (i) conflict with or result
in a breach of any provisions of AIP's Declaration of Trust; (ii) violate, or
conflict with, or result in a breach of any provision of, or constitute a
default (or an event which, with notice or lapse of time or both, would
constitute a default) under, or result in the termination or in a right of
termination or cancellation of, or accelerate the performance required by, or
result in the creation of any lien, security interest, charge or encumbrance
upon any of the properties of AIP or its Subsidiaries under, or result in being
declared void, voidable or without further binding effect, any of the terms,
conditions or provisions of any note, bond, mortgage, indenture, deed of trust
or any license, franchise, permit, lease, contract, agreement or other
instrument, commitment or obligation to which AIP or any of its Subsidiaries is
a party, or by which AIP or any of its Subsidiaries or any of their properties
is bound or affected, except for any of the foregoing matters which,
individually or in the aggregate, would not have an AIP Material Adverse
Effect; or (iii) other than the Regulatory Filings require any consent,
approval or authorization of, or declaration, filing or registration with, any
domestic governmental or regulatory authority, except where the failure to
obtain such consent, approval or authorization of, or declaration, filing or
registration with, any governmental or regulatory authority would not have an
AIP Material Adverse Effect.

         6.7.    SEC Documents.   (a)  AIP has made available or will make
available to RELP prior to September 30, 1997, the registration statements of
AIP filed with the SEC in connection with public offerings of AIP securities
since January 1, 1994 and all exhibits, amendments and supplements thereto (the
"AIP Registration Statements"), and each registration statement, report, proxy
statement or information statement and all exhibits thereto prepared by it or
relating to its properties since the effective date of the latest AIP
Registration Statement, each in the form (including exhibits and any amendments
thereto) filed with the SEC (collectively, the "AIP Reports"). The AIP Reports,
which were or will be filed with the SEC in a timely manner, constitute all
forms, reports and documents required to be filed by AIP under the Securities
Laws.





                                       12
<PAGE>   13
         (b)     To AIP's actual knowledge, as of their respective dates, the
AIP Reports (i) complied as to form in all material respects with the
applicable requirements of the Securities Laws, and (ii) did not contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements made therein, in the
light of the circumstances under which they were made, not misleading. To AIP's
actual acknowledge, each of the consolidated balance sheets of AIP included in
or incorporated by reference into the AIP Reports (including the related notes
and schedules) fairly presents the consolidated financial position of AIP and
the AIP Subsidiaries as of its date and each of the consolidated statements of
income, retained earnings and cash flows of AIP included in or incorporated by
reference into the AIP Reports (including any related notes and schedules)
fairly presents the results of operations, retained earnings or cash flows, as
the case may be, of AIP and the AIP Subsidiaries for the periods set forth
therein (subject, in the case of unaudited statements, to normal year-end audit
adjustments which would not be material in amount or effect), in each case in
accordance with generally accepted accounting principles consistently applied
during the periods involved, except as may be noted therein and except, in the
case of the unaudited statements, as permitted by the Securities Laws.

         (c)     Except as and to the extent set forth on the consolidated
balance sheet of AIP and its Subsidiaries at March 31, 1997, including all
notes thereto, or as set forth in the AIP Reports, neither AIP nor any of the
AIP Subsidiaries has any material liabilities or obligations of any nature
(whether accrued, absolute, contingent or otherwise) that would be required to
be reflected on, or reserved against in, a balance sheet of AIP or in the notes
thereto, prepared in accordance with generally accepted accounting principles
consistently applied, except liabilities arising in the ordinary course of
business since such date which would not have an AIP Material Adverse Effect.

         6.8.    Litigation.   To AIP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which AIP or any AIP Subsidiary is a party or by
which any of its properties or assets are bound or, to which any of its
directors, officers, or affiliates is a party or by which any of their
properties or assets are bound, and (ii) except as will be set forth in the AIP
Disclosure Letter, no actions, suits or proceedings pending against AIP or any
AIP Subsidiary or, to the knowledge of AIP, against any of its Trust Managers,
officers, or affiliates or, to the knowledge of AIP, threatened against AIP or
any AIP Subsidiary or against any of its Trust Managers, officers, or
affiliates, at law or in equity, or before or by any federal or state
commission, board, bureau, agency or instrumentality, that in the case of
clauses (i) or (ii) above are reasonably likely, individually or in the
aggregate, to have an AIP Material Adverse Effect.

         6.9.    Absence of Certain Changes.  Except as disclosed in the AIP
Reports filed with the SEC prior to the date hereof, (i) AIP and its
Subsidiaries have conducted their business only in the ordinary course of such
business (which, for purposes of this section only, shall include all
acquisitions of real estate properties and financing arrangements made in
connection therewith); (ii) there has not been any AIP Material Adverse Effect;
(iii) there has not been any declaration, setting aside or payment of any
dividend or other distribution with respect to the AIP Common Shares; and (iv)
there has not been any material change in AIP's accounting principles,
practices or methods.





                                       13
<PAGE>   14
         6.10.   Taxes.  (a)  Except as may be set forth in the AIP Disclosure
Letter, AIP and each of its Subsidiaries (i) has timely filed all federal,
state and foreign tax returns including, without limitation, information
returns and reports required to be filed by any of them for tax periods ended
prior to the date of this Agreement or requests for extensions have been timely
filed and any such request has been granted and has not expired and all such
returns are absolute and complete in all material respects, (ii) has paid or
accrued all taxes shown to be due and payable on such returns or which have
become due and payable pursuant to any assessment, deficiency notice, 30-day
letter or other notice received by it and (iii) has properly accrued all taxes
for such periods subsequent to the periods covered by such returns. Neither AIP
nor any of its Subsidiaries has received notice that the federal, state and
local income and franchise tax returns of AIP or any such Subsidiary has been
or will be examined by any taxing authority. Neither AIP nor any of its
Subsidiaries has executed or filed with the IRS or any other taxing authority
any agreement now in effect extending the period for assessment or collection
of any income or other taxes.

         (b)     Except as will be disclosed in the AIP Disclosure Letter,
neither AIP nor any of its Subsidiaries is a party to any pending action or
proceeding by any governmental authority for assessment or collection of taxes,
and no claim for assessment or collection of taxes has been asserted against
it. True, correct and complete copies of all federal, state and local income or
franchise tax returns filed by AIP and each of its Subsidiaries and all
communications relating thereto have been delivered to RELP or made available
to representatives of RELP or will be so delivered or made available prior to
September 30, 1997. AIP (i) has qualified to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable years ended December 31,
1985 through 1996, inclusive (ii) has operated, and intends to continue to
operate, in such a manner as to qualify to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable year ended on the
effective date of the Merger, and (iii) has not taken or omitted to take any
action which could result in, and each of the executive officers of AIP, each
acting in his respective capacity as such, has no actual knowledge of, a
challenge to its status as a REIT. AIP represents that each of its Subsidiaries
is a Qualified REIT Subsidiary as defined in Section 856 (i) of the Code.
Neither AIP nor any of its Subsidiaries holds any asset (i) the disposition of
which could be subject to rules similar to Section 1374 of the Code as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 6.10, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

         6.11.   Books and Records.  (a)  The books of account and other
financial records of AIP and its Subsidiaries are in all material respects
true, complete and correct, have been maintained in accordance with good
business practices, and are accurately reflected in all material respects in
the financial statements included in the AIP Reports.

         (b)     The minute books and other records of AIP and its Subsidiaries
contain in all material respects accurate records of all meetings and
accurately reflect in all material respects all other corporate action of the
shareholders and Trust Managers and any committees of the Board of Trust
Managers of AIP and its Subsidiaries.





                                       14
<PAGE>   15
         6.12.   Properties.  (a)  AIP and its Subsidiaries own fee simple
title to each of the real properties reflected on the most recent balance sheet
of AIP included in the AIP Reports or as may be identified in the AIP
Disclosure Letter (the "AIP Properties"), which are all of the real estate
properties owned by them, free and clear of Encumbrances. To AIP's actual
knowledge, the AIP Properties are not subject to any rights of way, written
agreements, laws, ordinances and regulations affecting building use or
occupancy, or reservations of an interest in title (collectively, "Property
Restrictions"), except for (i) Encumbrances and Property Restrictions that will
be set forth in the AIP Disclosure Letter, (ii) Property Restrictions imposed
or promulgated by law or any governmental body or authority with respect to
real property, including zoning regulations, provided they do not materially
adversely affect the current use of the property, (iii) Encumbrances and
Property Restrictions disclosed on existing title reports or surveys (in either
case copies of which title reports and surveys have been or will be delivered
or made available to RELP prior to September 30, 1997), and (iv) mechanics',
carriers', workmen's, repairmen's liens and other Encumbrances, Property
Restrictions and other limitations of any kind, if any, which have heretofore
been bonded (and that will be listed in the AIP Disclosure Letter) or which
individually or in the aggregate, do not exceed $100,000, do not materially
detract from the value of or materially interfere with the present use of any
of the AIP Properties subject thereto or affected thereby, and do not otherwise
materially impair business operations conducted by AIP and its Subsidiaries and
which have arisen or been incurred only in its construction activities or in
the ordinary course of business.

         (b)     Valid policies of title insurance have been issued insuring
AIP's or any of its Subsidiaries' fee simple title to the AIP Properties,
subject only to the matters disclosed above and as may be set forth in the AIP
Disclosure Letter, and such policies are, at the date hereof, in full force and
effect and no material claim has been made against any such policy. To AIP's
actual knowledge, except as will be set forth in the AIP Disclosure Letter, (i)
there is no certificate, permit or license from any governmental authority
having jurisdiction over any of the AIP Properties or any agreement, easement
or other right which is necessary to permit the lawful use and operation of the
buildings and improvements on any of the AIP Properties or which is necessary
to permit the lawful use and operation of all driveways, roads and other means
of egress and ingress to and from any of the AIP Properties that has not been
obtained and is not in full force and effect, or of any pending threat of
modification or cancellation of any of same; (ii) neither AIP nor its
Subsidiaries has received written notice of any material violation of any
federal, state or municipal law, ordinance, order, regulation or requirement
affecting any portion of any of the AIP Properties issued by any governmental
authority; (iii) there are no structural defects relating to the AIP Properties
and no AIP Properties whose building systems are not in working order in any
material respect; and (iv) there is (A) no physical damage to any AIP Property
in excess of $100,000 for which there is no insurance in effect covering the
cost of the restoration, (B) no current renovation to any AIP Property the cost
of which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any AIP Property the cost of which exceeds $100,000.

         (c)     Except as will be set forth in the AIP Disclosure Letter, AIP
or its Subsidiaries have received no notice to the effect that and there are no
(A) condemnation or rezoning proceedings that are pending or threatened with
respect to any of the AIP Properties or (B) any zoning, building or similar
laws, codes, ordinances, orders or regulations that are or will be violated by
the continued maintenance, operation or use of any buildings or other
improvements on any of the AIP Properties or by the continued maintenance,
operation or use of the parking areas in any material respect. All





                                       15
<PAGE>   16
work to be performed, payments to be made and actions to be taken by AIP or its
Subsidiaries prior to the date hereof pursuant to any agreement entered into
with a governmental body or authority in connection with a site approval,
zoning reclassification or other similar action relating to the AIP Properties
(e.g., Local Improvement District, Road Improvement District, Environmental
Mitigation) has been performed, paid or taken, as the case may be, and AIP is
not aware of any planned or proposed work, payments or actions that may be
required after the date hereof pursuant to such agreements, except as will be
set forth in the AIP Disclosure Letter.

         6.13.   Environmental Matters.  To the actual knowledge of AIP, none
of AIP, any of its Subsidiaries or, any other person has caused or permitted
(i) the unlawful presence of any Hazardous Materials on any of the AIP
Properties, or (ii) any unlawful spills, releases, discharges or disposal of
Hazardous Materials to have occurred or be presently occurring on or from the
AIP Properties as a result of any construction on or operation and use of such
properties, which presence or occurrence would, individually or in the
aggregate, have an AIP Material Adverse Effect; and in connection with the
construction on or operation and use of the AIP Properties, AIP and its
Subsidiaries have not failed to comply, in any material respect, with any
applicable local, state and federal environmental laws, regulations, ordinances
and administrative and judicial orders relating to the generation, recycling,
reuse, sale, storage, handling, transport and disposal of any Hazardous
Materials.

         6.14.   Labor Matters.   Neither AIP nor any of its Subsidiaries is a
party to, or bound by, any collective bargaining agreement, contract or other
agreement or understanding with a labor union or labor union organization.
There is no unfair labor practice or labor arbitration proceeding pending or,
to the knowledge of the executive officers of AIP, threatened against AIP or
its Subsidiaries relating to their business, except for any such proceeding
which would not have an AIP Material Adverse Effect. To the knowledge of AIP,
there are no organizational efforts with respect to the formation of a
collective bargaining unit presently being made or threatened involving
employees of AIP or any of its Subsidiaries.

         6.15.   No Brokers.  Except for the fee payable to Prudential
Securities Incorporated ("Prudential") as described in Section 6.16 below, AIP
has not entered into any contract, arrangement or understanding  with any
person or firm which may result in the obligation of AIP or RELP to pay any
finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby. AIP is not aware of any claim for
payment of any finder's fees, brokerage or agent's commissions or other like
payments in connection with the negotiations leading to this Agreement or the
consummation of the transactions contemplated hereby.

         6.16.   Opinion of Financial Advisor.  AIP has retained Prudential to
review the transaction contemplated by this Agreement and to issue an opinion
as to the fairness to AIP, from a financial point of view, of the consideration
to be paid by AIP pursuant to the Merger.

         6.17.   RELP Share Ownership.  Except as may be set forth in the AIP
Disclosure Letter, neither AIP nor any of its Subsidiaries owns any RELP
Interests or other securities convertible into RELP interests.





                                       16
<PAGE>   17
         6.18.   AIP Common Shares.  The issuance and delivery by AIP of AIP
Common Shares in connection with the Merger and this Agreement have been duly
and validly authorized by all necessary action on the part of AIP except for
the approval of its shareholders contemplated by this Agreement. The AIP Common
Shares to be issued in connection with the Merger and this Agreement, when
issued in accordance with the terms of this Agreement, will be validly issued,
fully paid and nonassessable, except that shareholders may be subject to
further assessment with respect to certain claims for tort, contract, taxes,
statutory liability and otherwise in some jurisdictions to the extent such
claims are not satisfied by AIP.

         6.19.   Convertible Securities.  AIP has no outstanding options,
warrants or other securities exercisable for, or convertible into, shares of
AIP Common Shares, the terms of which would require any anti-dilution
adjustments by reason of the consummation of the transactions contemplated
hereby, except the preemptive rights held by certain clients of Morgan Stanley
Asset Management, Inc. and held by MS Real Estate Special Situations, Inc. and
the convertible debt securities held by Realco.

         6.20.   Related Party Transactions.  Set forth in the AIP Disclosure
Letter will be a list of all arrangements, agreements and contracts entered
into by AIP or any of its Subsidiaries with (i) any person who is an officer,
Trust Manager or affiliate of AIP or any of its Subsidiaries, any relative of
any of the foregoing or any entity of which any of the foregoing is an
affiliate or (ii) any person who acquired AIP Common Shares in a private
placement. The copies of such documents, all of which have been or will be
delivered or made available to RELP prior to September 30, 1997, are or will be
true, complete and correct when delivered or made available.

         6.21.   Contracts and Commitments.  The AIP Disclosure Letter will set
forth (i) all unsecured notes or other obligations of AIP and AIP Subsidiaries
which individually may result in total payments in excess of $100,000, (ii)
notes, debentures, bonds and other evidence of indebtedness which are secured
or collateralized by mortgages, deeds of trust or other security interests in
the AIP Properties or personal property of AIP and its Subsidiaries, and (iii)
each commitment entered into by AIP or any of its Subsidiaries which
individually may result in total payments or liability in excess of $100,000.
Copies of the foregoing have been or will be delivered or made available to
RELP prior to September 30, 1997, will be listed on the AIP Disclosure Letter
and are or will be materially true and correct when delivered or made
available. None of AIP or any of its Subsidiaries has received any notice of a
default that has not been cured under any of the documents described in clause
(i) or (ii) above or is in default respecting any payment obligations
thereunder beyond any applicable grace periods. All options of AIP or any of
its Subsidiaries to purchase real property will be set forth on the AIP
Disclosure Letter and such options and AIP's or its Subsidiaries' rights
thereunder are in full force and effect. All joint venture agreements to which
AIP or any of its Subsidiaries is a party will be set forth on the AIP
Disclosure Letter and AIP or its Subsidiaries are not in default with respect
to any obligations, which individually or in the aggregate are material,
thereunder.

         6.22.   Development Rights.  Set forth in the AIP Disclosure Letter
will be a list of all material agreements entered into by AIP or any of its
Subsidiaries relating to the development, rehabilitation, capital improvement
or construction of office buildings, industrial facilities or other real estate
properties which development or construction has not been substantially
completed as of





                                       17
<PAGE>   18
the date of this Agreement. Such agreements, true, complete and correct copies
of all of which have been or will be delivered or made available to RELP prior
to September 30, 1997, will be listed in the AIP Disclosure Letter.

         6.23.   Certain Payments Resulting From Transactions.  The execution
of, and performance of the transactions contemplated by, this Agreement will
not (either alone or upon the occurrence of any additional or subsequent
events) (i) constitute an event under any AIP Benefit Plan, policy, practice,
agreement or other arrangement or any trust or loan (the "Employee
Arrangements") that will or may result in any payment (whether of severance pay
or otherwise), acceleration, forgiveness of indebtedness, vesting,
distribution, increase in benefits or obligation to fund benefits with respect
to any employee, director or consultant of AIP or any of its Subsidiaries
unless such rights have been waived by any such person, or (ii) result in the
triggering or imposition of any restrictions or limitations on the right of AIP
or RELP to amend or terminate any Employee Arrangement and receive the full
amount of any excess assets remaining or resulting from such amendment or
termination, subject to applicable taxes. No payment or benefit which will be
required to be made pursuant to the terms of any agreement, commitment or AIP
Benefit Plan, as a result of the transactions contemplated by this Agreement,
to any officer, director or employee of AIP or any of its Subsidiaries, will be
characterized as an "excess parachute payment" within the meaning of Section
280G(b)(1) of the Code.

                            ARTICLE VII.  COVENANTS

         7.1.    Acquisition Proposals.   Prior to the Effective Time, RELP and
AIP each agree (i) that neither of them nor any of their Subsidiaries shall,
and each of them shall direct and use its best efforts to cause its respective
officers, General Partner, limited partners, Trust Managers, employees, agents,
affiliates and representatives (including, without limitation, any investment
banker, attorney or accountant retained by it or any of its Subsidiaries), as
applicable, not to, initiate, solicit or encourage, directly or indirectly, any
inquiries or the making or implementation of any proposal or offer (including,
without limitation, any proposal or offer to its shareholders) with respect to
a merger, acquisition, tender offer, exchange offer, consolidation or similar
transaction involving, or any purchase of all or any significant portion of the
assets or any equity securities (or any debt securities convertible into equity
securities) of, such party or any of its Subsidiaries, other than the
transactions contemplated by this Agreement (any such proposal or offer being
hereinafter referred to as an "Acquisition Proposal") or engage in any
negotiations concerning, or provide any confidential information or data to, or
have any discussions with, any person relating to an Acquisition Proposal, or
otherwise facilitate any effort or attempt to make or implement an Acquisition
Proposal; (ii) that it will immediately cease and cause to be terminated any
existing activities, discussions or negotiations with any parties conducted
heretofore with respect to any of the foregoing and each will take the
necessary steps to inform the individuals or entities referred to above of the
obligations undertaken in this Section 7.1; and (iii) that it will notify the
other party immediately if any such inquiries or proposals are received by, any
such information is requested from, or any such negotiations or discussions are
sought to be initiated or continued with, it; provided, however, that nothing
contained in this Section 7.1 shall prohibit the Board of Directors of the
General Partner of RELP (the "Board of Directors") or the Board of Trust
Managers from (x) furnishing information to or entering into discussions or
negotiations with, any person or entity that makes an unsolicited bona fide
Acquisition Proposal, if, and only to the extent that, (A) the Board





                                       18
<PAGE>   19
of Directors or Board of Trust Managers, as applicable, determines in good
faith that such action is required for it to comply with its fiduciary duties
to limited partners or shareholders, as applicable,  imposed by law as advised
by counsel, (B) prior to furnishing such information to, or entering into
discussions or negotiations with, such person or entity, such party provides
written notice to the other party to this Agreement to the effect that it is
furnishing information to, or entering into discussions with, such person or
entity, and (C) subject to any confidentiality agreement with such person or
entity (which such party determined in good faith was required to be executed
in order for the Board of Directors or Board of Trust Managers, as applicable,
to comply with its fiduciary duties to limited partners or shareholders, as
applicable,  imposed by law as advised by counsel), such party keeps the other
party to this Agreement informed of the status (but not the terms) of any such
discussions or negotiations; and (y) to the extent applicable, complying with
Rule 14e-2 promulgated under the Exchange Act with regard to an Acquisition
Proposal.

         Nothing in this Section 7.1 shall (i) permit any party to terminate
this Agreement (except as specifically provided in Article IX hereof), (ii)
permit any party to enter into any agreement with respect to an Acquisition
Proposal during the term of this Agreement (it being agreed that during the
term of this Agreement, no party shall enter into any agreement with any person
that provides for, or in any way facilitates, an Acquisition Proposal (other
than a confidentiality agreement in customary form)), or (iii) affect any other
obligation of any party under this Agreement.

         7.2.    Conduct of Businesses.

         (i)     Prior to the Effective Time, except as may be set forth in
the RELP Disclosure Letter or the AIP Disclosure Letter or as contemplated by
this Agreement, unless the other party has consented in writing thereto, AIP
and RELP:

         (a)     Shall use their reasonable efforts, and shall cause each of
                 their respective Subsidiaries to use their reasonable efforts,
                 to preserve intact their business organizations and goodwill
                 and keep available the services of their respective officers
                 and employees;

         (b)     Shall confer on a regular basis with one or more
                 representatives of the other to report operational matters of
                 materiality and, subject to Section 7.1, any proposals to
                 engage in material transactions;

         (c)     Shall promptly notify the other of any material emergency or
                 other material change in the condition (financial or
                 otherwise) of the  business, properties, assets or
                 liabilities, or any material governmental complaints,
                 investigations or hearings (or communications indicating that
                 the same may be contemplated), or the breach in any material
                 respect of any representation, warranty, covenant or agreement
                 contained herein;

         (d)     Shall not pay quarterly dividends or make distributions
                 payable with respect to the AIP Common Shares and RELP
                 Partnership Interests, respectively; and

         (e)     Shall promptly deliver to the other true and correct copies of
                 any report, statement or schedule filed with the SEC
                 subsequent to the date of this Agreement.





                                       19
<PAGE>   20
         (ii)    Prior to the Effective Time, except as may be set forth in the
RELP Disclosure Letter, unless AIP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, RELP:

         (a)     Shall conduct its operations according to its usual, regular
                 and ordinary course in substantially the same manner as
                 heretofore conducted;

         (b)     Shall not amend the RELP Organizational Documents;

         (c)     Shall not (i) except pursuant to the exercise of options,
                 warrants, conversion rights and other contractual rights
                 existing on the date hereof and disclosed pursuant to this
                 Agreement, issue any RELP Interests, make any distribution,
                 effect any recapitalization or other similar transaction, (ii)
                 grant, confer or award any option, warrant, conversion right
                 or other right not existing on the date hereof to acquire any
                 RELP Interest, (iii) increase any compensation or enter into
                 or amend any employment agreement with any of its present or
                 future officers or directors of the General Partner, or (iv)
                 adopt any new employee benefit plan or amend any existing
                 employee benefit plan in any material respect, except for
                 changes which are less favorable to participants in such
                 plans;

         (d)     Shall not declare, set aside or make any distribution or
                 payment with respect to any RELP Interest or directly or
                 indirectly redeem, purchase or otherwise acquire any RELP
                 Interest, or make any commitment for any such action;

         (e)     Shall not sell or otherwise dispose of (i) any RELP
                 Properties, or (ii) except in the ordinary course of business,
                 any of its other assets which are material, individually or in
                 the aggregate;

         (f)     Shall not make any loans, advances or capital contributions
                 to, or investments in, any other person;

         (g)     Shall not pay, discharge or satisfy any claims, liabilities or
                 obligations (absolute, accrued, asserted or unasserted,
                 contingent or otherwise), other than the payment, discharge or
                 satisfaction in the ordinary course of business consistent
                 with past practice or in accordance with their terms, of
                 liabilities reflected or reserved against in, or contemplated
                 by, the most recent consolidated financial statements (or the
                 notes thereto) of RELP included in the RELP Reports or
                 incurred in the ordinary course of business consistent with
                 past practice;

         (h)     Shall not enter into any commitment which individually may
                 result in total payments or liability by or to it in excess of
                 $250,000 in the case of any one commitment or in excess of
                 $500,000 for all commitments;





                                       20
<PAGE>   21
         (i)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment with any officer, director or
                 affiliate of RELP or  its General Partner except to the extent
                 the same occur in the ordinary course of business consistent
                 with past practice and would not have a RELP Material Adverse
                 Effect; and

         (j)     Shall not enter into or terminate any lease representing
                 annual revenues of $100,000 or more.

         (iii)   Prior to the Effective Time, except as may be set forth in the
AIP Disclosure Letter, unless RELP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, AIP:

         (a)     Shall, and shall cause each of its Subsidiaries to, conduct
                 its operations according to their usual, regular and ordinary
                 course in substantially the same manner as heretofore
                 conducted;

         (b)     Shall not amend its Declaration of Trust or Bylaws except as
                 contemplated by this Agreement;

         (c)     Shall not (i) except pursuant to the exercise of options,
                 warrants, conversion rights and other contractual rights
                 (including AIP's existing dividend reinvestment plan) existing
                 on the date hereof and disclosed pursuant to this Agreement,
                 issue any shares of its capital stock, effect any share split,
                 reverse share split, share dividend, recapitalization or other
                 similar transaction, (ii) grant, confer or award any option,
                 warrant, conversion right or other right not existing on the
                 date hereof to acquire any shares of its capital shares
                 (except pursuant to any employee incentive plan approved by
                 shareholders), (iii) amend any employment agreement with any
                 of its present or future officers or Trust Managers, or (iv)
                 adopt any new employee benefit plan (including any share
                 option, share benefit or share purchase plan) except the
                 employee incentive plan to be voted on at its shareholder
                 meeting for the fiscal year ended December 31, 1995;

         (d)     Shall not declare, set aside or pay any dividend or make any
                 other distribution or payment with respect to any Common
                 Shares or directly or indirectly redeem, purchase or otherwise
                 acquire  any Common Shares or capital stock of any of its
                 Subsidiaries, or make any commitment for any such action;

         (e)     Except as will be set forth in the AIP Disclosure Letter,
                 shall not, and shall not permit any of its Subsidiaries to,
                 sell or otherwise dispose of (i) any AIP Properties or any of
                 its capital stock of or other interests in Subsidiaries or
                 (ii) except in the ordinary course of business, any of its
                 other assets which are material, individually or in the
                 aggregate;

         (f)     Shall not, and shall not permit any of its Subsidiaries to,
                 make any loans, advances or capital contributions to, or
                 investments in, any other person other than in connection with
                 the sale of properties;





                                       21
<PAGE>   22
         (g)     Shall not, and shall not permit any of its Subsidiaries to,
                 pay, discharge or satisfy any claims, liabilities or
                 obligations (absolute, accrued, asserted or unasserted,
                 contingent or otherwise), other than the payment, discharge or
                 satisfaction in the ordinary course of business consistent
                 with past practice or in accordance with their terms, of
                 liabilities reflected or reserved against in, or contemplated
                 by, the most recent consolidated financial statements (or the
                 notes thereto) of AIP included in the AIP Reports or incurred
                 in the ordinary course of business consistent with past
                 practice;

         (h)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment which individually may result in
                 total payments or liability by or to it in excess of $500,000
                 in the case of any one commitment or in excess of $500,000 for
                 all commitments; and

         (i)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment with any officer, Trust Manager or
                 affiliate of AIP or any of its Subsidiaries, except as herein
                 or in the AIP Disclosure Letter provided and except in the
                 ordinary course of business.

For purposes of this Section 7.2, any consent shall be deemed to be
unreasonably delayed if notice of consent or withholding of consent is not
received within three days of request.  Further, if no response is received by
the end of business on such third day, the party receiving the request shall be
deemed to have consented to such action.

         7.3     Meetings of Shareholders and Partners.  Each of AIP and RELP
will take all action necessary in accordance with applicable law and its
organizational documents  to convene a meeting of its shareholders or partners,
as applicable,  as promptly as practicable to consider and vote upon or
otherwise to obtain the consent of its shareholders or partners, as applicable,
to (i) in the case of AIP, approve this Agreement and the transactions
contemplated hereby, and (ii) in the case of RELP, approve this Agreement and
the transactions contemplated hereby. The Board of Trust Managers and the
General Partner shall each recommend such approval and AIP and RELP shall each
take all lawful action to solicit such approval, including, without limitation,
timely mailing the Proxy Statement/Prospectus (as defined in Section 7.7);
provided, however, that such recommendation or solicitation is subject to any
action taken by, or upon authority of, the Board of Trust Managers or the
General Partner, as the case may be, in the exercise of its good faith judgment
as to its fiduciary duties to its shareholders or partners, as applicable,
imposed by law as advised by counsel. AIP and RELP shall coordinate and
cooperate with respect to the timing of such meetings and shall use their best
efforts to hold such meetings on the same day.

         7.4.     Filings; Other Action.  Subject to the terms and conditions
herein provided, RELP and AIP shall: (a) use all reasonable efforts to
cooperate with one another in (i) determining which filings are required to be
made prior to the Effective Time with, and which consents, approvals, permits
or authorizations are required to be obtained prior to the Effective Time from
governmental or regulatory authorities of the United States and the several
states in connection with the execution and delivery of this Agreement and the
consummation of the transactions contemplated hereby and (ii) timely making all
such filings and timely seeking all such consents, approvals, permits or
authorizations; (b) use all reasonable efforts to obtain in writing any
consents required from third





                                       22
<PAGE>   23
parties in form reasonably satisfactory to RELP and AIP necessary to effectuate
the Merger; and (c) use all reasonable efforts to take, or cause to be taken,
all other action and do, or cause to be done, all other things necessary,
proper or appropriate to consummate and make effective the transactions
contemplated by this Agreement. If, at any time after the Effective Time, any
further action is necessary or desirable to carry out the purpose of this
Agreement, the proper officers and directors of AIP and the General Partner
shall take all such necessary action.

         7.5.    Inspection of Records.  From the date hereof to the Effective
Time, each of RELP and AIP shall allow all designated officers, attorneys,
accountants and other representatives of the other access at all reasonable
times to the records and  files, correspondence, audits and properties, as well
as to all information relating to commitments, contracts, titles and financial
position, or otherwise pertaining to the business and affairs of RELP and AIP
and their respective Subsidiaries.

         7.6.    Publicity.  RELP and AIP shall, subject to their respective
legal obligations (including requirements of stock exchanges and other similar
regulatory bodies), consult with each other, and use reasonable efforts to
agree upon the text of any press release before issuing any such press release
or otherwise making public statements with respect to the transactions
contemplated hereby and in making any filings with any federal or state
governmental or regulatory agency or with any national securities exchange with
respect thereto.

         7.7.    Registration Statement.  AIP and RELP shall cooperate and
promptly prepare and AIP shall file with the SEC as soon as practicable a
Registration Statement on Form S-4 (the "Form S-4") under the Securities Act,
with respect to the AIP Common Shares issuable in the Merger, a portion of
which Registration Statement shall also serve as the joint proxy statement with
respect to the meetings of the shareholders and partners, respectively, of AIP
and RELP in connection with the Merger (the "Proxy Statement/Prospectus"). The
respective parties will cause the Proxy Statement/Prospectus and the Form S-4
to comply as to form in all material respects with the applicable provisions of
the Securities Act, the Exchange Act and the rules and regulations promulgated
thereunder. AIP shall use all reasonable efforts, and RELP will cooperate with
AIP to have the Form S-4 declared effective by the SEC as promptly as
practicable.  AIP shall use its best efforts to obtain, prior to the effective
date of the Form S-4, all necessary state securities law or "Blue Sky" permits
or approvals required to carry out the transactions contemplated by this
Agreement and will pay all expenses incident thereto. AIP agrees that the Proxy
Statement/Prospectus and each amendment or supplement thereto, at the time of
mailing thereof and at the time of the respective meetings of shareholders and
partners, respectively, of AIP and RELP, or, in the case of the Form S-4 and
each amendment or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading; provided, however, that the foregoing shall not apply to the
extent that any such untrue statement of a material fact or omission to state a
material fact was made by AIP in reliance upon and in conformity with written
information concerning RELP furnished to AIP by RELP specifically for use in
the Proxy Statement/Prospectus. RELP agrees that the written information
provided by it specifically for inclusion in the Proxy Statement/Prospectus and
each amendment or supplement thereto, at the time of mailing thereof and at the
time of the respective meetings of shareholders and partners, respectively, of
AIP and RELP, or, in the case of written information provided by RELP
specifically for inclusion in the Form S-4





                                       23
<PAGE>   24
or any amendments or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading. AIP will advise RELP, promptly after it receives notice
thereof, of the time when the Form S-4 has become effective or any supplement
or amendment has been filed, the issuance of any stop order, the suspension of
the qualification of the AIP Common Shares issuable in connection with the
Merger for offering or sale in any jurisdiction, or any request by the SEC for
amendment of the Proxy Statement/Prospectus or the Form S-4 or comments thereon
and responses thereto or requests by the SEC for additional information.

         7.8.    Listing Application.  AIP shall promptly prepare and submit to
the NYSE a listing application covering the AIP Common Shares issuable in the
Merger, and shall use its reasonable efforts to obtain, prior to the Effective
Time, approval for the listing of such AIP Common Shares, subject to official
notice of issuance.

         7.9.    Further Action.  Each party hereto shall, subject to the
fulfillment at or before the Effective Time of each of the conditions of
performances set forth herein or the waiver thereof, perform such further acts
and execute such documents as may reasonably be required to effect the Merger.

         7.10.   Expenses.  Subject to Section 9.5, if the Merger is approved
by RELP's partners, all transaction costs of the proposed consolidation shall
be paid by AIP.  If three of the four limited partnerships party to the Proxy
Statement/Prospectus (the "Other RELPS") do not approve their proposed merger
into AIP, Realco shall reimburse AIP for AIP's expenses relating to the
proposed merger up to $250,000.  If RELP and the Other RELPS approve their
proposed merger into AIP, but the shareholders of AIP do not approve the
proposer merger, and if Realco voted its AIP Common Shares in favor of such
mergers, AIP will reimburse RELP and the Other RELPS for all expenses they
incurred in connection with the proposed merger.  Any expenses to be reimbursed
hereunder shall include, but not be limited to, costs of fairness opinions,
property appraisals, engineering and environmental reports, title policies,
accounting fees, legal fees, printing and solicitation expenses.  RELP will
bear the costs of preparing its initial fairness opinion, with later
reimbursement by AIP in the event the Merger is approved by RELP's partners.
If the limited partners of RELP fail to approve the proposed Merger, then
Realco will reimburse AIP for the RELP's expenses (to the extent paid by AIP)
as follows: the actual cost of such RELP's fairness opinion, legal fees up to
$80,000, and the actual cost or the Allocable Share  (if the actual cost is not
separately determined), of RELP's accounting fees, engineering and
environmental reports, printing and solicitation expenses.  Allocable Share,
for this purpose, shall be the ratio of such RELP's net book value of assets at
March 31, 1997 to the total net book value of all of the assets of RELP and the
Other RELPS at March 31, 1997.

         7.11.   Indemnification.  For a period of six years from and after the
Effective Time, AIP shall indemnify the partners, or agents of RELP who at any
time prior to the Effective Time were entitled to indemnification under the
Agreement of Limited Partnership of RELP existing on the date hereof to the
same extent as such partners or agents are entitled to indemnification under
such Agreement of Limited Partnership in respect of actions or omissions
occurring at or prior to the Effective Time (including, without limitation, the
transactions contemplated by this Agreement).





                                       24
<PAGE>   25
         7.12.   REIT Status.   From and after the date and until the Effective
Time, neither AIP nor RELP nor any of their respective Subsidiaries or other
affiliates shall (i) knowingly take any action, or knowingly fail to take any
action, that would jeopardize qualification of AIP as a REIT within the meaning
of Sections 856 through 859 of the Code; or (ii) enter into any contract,
agreement, commitment or arrangement with respect to the foregoing.

         7.13.   Survival of RELP Obligations; Assumption of RELP Liabilities
by AIP.  All of the obligations of RELP that are outstanding at the Closing
shall survive the Closing and shall not be merged therein. Upon the
consummation of the Merger, such obligations shall be assumed, automatically,
by AIP; provided, however, that such assumption shall not impose upon or expose
AIP to any liability for which RELP was not liable, and provided, further, that
AIP shall be entitled to the same defenses, offsets and counterclaims to which
RELP would have been entitled, but for the Merger.

         7.14.   Third Party Consents.  AIP and RELP each shall take all
necessary corporate and other action and will use its commercially reasonable
efforts to obtain the consents and applicable approvals from third parties that
may be required to enable it to carry out the transactions contemplated by this
Agreement.

         7.15.   Efforts to Fulfill Conditions.  AIP and RELP each shall use
commercially reasonable efforts to insure that all conditions precedent to its
obligations hereunder are fulfilled at or prior to the Closing.

         7.16.   Representations, Warranties and Conditions Prior to Closing.
AIP and RELP each shall use its commercially reasonable efforts to cause its
representations and warranties contained in this Agreement to be true and
correct on and as of the Closing Date in all material respects. Prior to
Closing, AIP and RELP each shall promptly notify the other in writing (i) if
any representation or warranty contained in this Agreement is discovered to be
or becomes untrue or (ii) if AIP or RELP fails to perform or comply with any of
its covenants or agreements contained in this Agreement or it is reasonably
expected that it will be unable to perform or comply with any of its covenants
or agreements contained in this Agreement.

         7.17.   Cooperation of the Parties.  AIP and RELP each will cooperate
with the other in supplying such information as may be reasonably requested by
the other in connection with obtaining consents or approvals to the
transactions contemplated by this Agreement.

         7.18.   Lock-Ups.  The General Partner shall use its best efforts
prior to the Closing to have each of its directors and officers and Realco
execute a 90-day lock-up agreement in a form (reasonably acceptable to RELP)
supplied to RELP by AIP. The executed agreements will be delivered to AIP at
the Closing.  AIP shall use its best efforts prior to the Closing to have each
of its Trust Managers and officers execute a 90-day lock-up agreement, in a
form (reasonably acceptable to AIP) supplied to AIP by RELP. The agreements
will be delivered to RELP at the Closing.





                                       25
<PAGE>   26
                           ARTICLE VIII.  CONDITIONS

         8.1.    Conditions to Each Party's Obligations to Effect the Merger.
The respective obligation of each party to effect the Merger shall be subject
to the fulfillment at or prior to the Closing Date of the following conditions:

         (a)     This Agreement and the transactions contemplated hereby shall
                 have been approved in the manner required by the Declaration
                 of Trust  and Bylaws and Agreement of Limited Partnership of
                 AIP and RELP, respectively, and by applicable law or by
                 applicable regulations of any stock exchange or other
                 regulatory body by the holders of the AIP Common Shares and
                 RELP Interests entitled to vote thereon.

         (b)     Neither of the parties hereto shall be subject to any order or
                 injunction of a court of competent jurisdiction which
                 prohibits the consummation of the transactions contemplated by
                 this Agreement. In the event any such order or injunction
                 shall have been issued, each party agrees to use its
                 reasonable efforts to have any such injunction lifted.

         (c)     The Form S-4 shall have become effective and all necessary
                 state securities law or "Blue Sky" permits or approvals
                 required to carry out the transactions contemplated by this
                 Agreement shall have been obtained and no stop order with
                 respect to any of the foregoing shall be in effect.

         (d)     AIP shall have obtained the approval for the listing of the
                 AIP Common Shares issuable in the Merger on the NYSE, subject
                 to official notice of issuance.

         (e)     All consents, authorizations, orders and approvals of (or
                 filings or registrations with) any governmental commission,
                 board, other regulatory body or third parties required in
                 connection with the execution, delivery and performance of
                 this Agreement shall have been obtained or made, except for
                 filings in connection with the Merger and any other documents
                 required to be filed after the Effective Time and except where
                 the failure to have obtained or made any such consent,
                 authorization, order, approval, filing or registration would
                 not have a material adverse effect on the business, results of
                 operations or financial condition of AIP and RELP (and their
                 respective Subsidiaries), taken as a whole, following the
                 Effective Time.

         8.2     Conditions to Obligations of RELP to Effect the Merger.  The
obligation of RELP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by
RELP:

         (a)     AIP shall have performed its agreements contained in this
                 Agreement required to be performed on or prior to the Closing
                 Date and the representations and warranties of AIP contained
                 in this Agreement shall be true and correct in all material
                 respects as of the Closing Date as if made on the Closing
                 Date, and RELP shall have received a certificate of the
                 President or an Executive or Senior Vice President of AIP,
                 dated the Closing Date, certifying to such effect.





                                       26
<PAGE>   27
         (b)     RELP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by AIP and approved by
                 RELP, dated the Closing Date, to the effect that AIP met the
                 requirements for qualification and taxation as a REIT for its
                 taxable year ending December 31, 1985, and has met the
                 requirements for qualification and taxation as a REIT for its
                 taxable years 1986 through 1996; AIP's diversity of equity
                 ownership, operations through the Closing Date and proposed
                 method of operation for future periods should allow it to
                 qualify as a REIT for its taxable year ending December 31,
                 1997; and the discussion contained under the caption "Material
                 Federal Income Tax Consequences" in the Proxy
                 Statement/Prospectus accurately reflects existing law and
                 fairly addresses the material Federal income tax issues
                 described therein.  In rendering its opinion, said counsel
                 shall be entitled to rely as to any factual matter upon
                 certificates given by executive officers and other duly
                 authorized representatives of RELP and AIP and shall be
                 entitled to assume that the covenants set forth in Article VII
                 shall be fully complied with.

         (c)     From the date of the Agreement through the Effective Time,
                 there shall not have occurred any change in the financial
                 condition, business or operations of AIP and its Subsidiaries,
                 taken as a whole, that would have or would be reasonably
                 likely to have an AIP Material Adverse Effect other than any
                 such change that affects both RELP and AIP in a substantially
                 similar manner.

         (d)     The opinion of Houlihan addressed to RELP that the Purchase
                 Price is fair, from a financial point of view, to the partners
                 of RELP shall not have been withdrawn or materially modified.

         (e)     RELP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by AIP and approved by
                 RELP, dated the Closing Date, as to such customary matters as
                 RELP may reasonably request, such opinion to be reasonably
                 satisfactory to RELP.

         8.3     Conditions to Obligation of AIP to Effect the Merger.  The
obligations of AIP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by AIP:

         (a)     RELP shall have performed its agreements contained in this
                 Agreement required to be performed on or prior to the Closing
                 Date and the representations and warranties of RELP contained
                 in this Agreement shall be true and correct in all material
                 respects as of the Closing Date as if made on the Closing Date
                 and AIP shall have received a certificate of the Chief
                 Executive Officer, President or an Executive Vice President of
                 the General Partner dated the Closing Date, certifying to such
                 effect.

         (b)     AIP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by RELP and approved by
                 AIP, dated the Closing Date, to the effect that the
                 consummation of the Merger will not result in AIP's failure to
                 continue to satisfy the requirements for qualification as a
                 REIT for federal income tax purposes. In rendering its
                 opinion, said counsel shall be entitled to rely as to any
                 factual matter





                                       27
<PAGE>   28
                 upon certificates given by executive officers and other duly
                 authorized representatives of AIP and RELP and shall be
                 entitled to assume that the covenants of Article VII shall be
                 fully complied with.

         (c)     From the date of this Agreement through the Effective Time,
                 there shall not have occurred any change in the financial
                 condition, business or operations of RELP and its
                 Subsidiaries, taken as a whole, that would have or would be
                 reasonably likely to have an RELP Material Adverse Effect,
                 other than any such change that affects both RELP and AIP in a
                 substantially similar manner.

         (d)     Each person listed on Exhibit 8.3(d) attached hereto shall
                 have delivered to AIP a written agreement to the effect that
                 such person will not offer to sell, sell or otherwise dispose
                 of any shares of AIP Common Stock issued in the Merger,
                 except, in each case, pursuant to an effective registration
                 statement or in compliance with Rule 145, as amended from time
                 to time, or in a transaction which, in the opinion of legal
                 counsel reasonably satisfactory to AIP, is exempt from the
                 registration requirements of the Securities Act and that the
                 certificates representing the AIP shares issued to him or her
                 in the Merger may bear a legend to such effect.

         (e)     The opinion of Prudential addressed to the Board of Trust
                 Managers of AIP that the consideration to be paid by AIP
                 pursuant to the Merger is fair, from a financial point of
                 view, to AIP shall not have been withdrawn or materially
                 modified.

         (f)     AIP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by RELP and approved by
                 AIP, dated the Closing Date, as to such customary matters as
                 AIP may reasonably request, such opinion to be reasonably
                 satisfactory to AIP.

         (g)     The limited partners of at least two of the Other RELPS shall
                 have approved the merger of such limited partnership with and
                 into AIP.

                            ARTICLE IX.  TERMINATION

         9.1     Termination by Mutual Consent.  This Agreement may be
terminated and the Merger may be abandoned at any time prior to the Effective
Time, before or after the approval of this Agreement by the partners of RELP or
the shareholders of AIP or by the mutual written consent of AIP and RELP, with
the prior approval of their respective Board of Trust Managers and General
Partner.

         9.2     Termination by Either AIP or RELP.  This Agreement may be
terminated and the Merger may be abandoned by action of the General Partner of
RELP or the Board of Trust Managers of AIP if (i) the Merger shall not have
been consummated by March 31, 1998, (ii) a meeting of RELP's partners shall
have been duly convened and held and the approval of RELP's partners required
by Section 8.1(a) shall not have been obtained at such meeting or at any
adjournment thereof, (iii) a meeting of AIP's shareholders shall have been duly
convened and held and the approval of AIP's shareholders required by Section
8.1(a) shall not have been obtained at such





                                       28
<PAGE>   29
meeting or at any adjournment thereof, (iv) as a result of due diligence
investigation by one of the parties hereto, it is determined in good faith by
such party that certain facts or circumstances not previously known by such
party constitute a Material Adverse Effect on the business, results of
operations or financial condition of the other party, (v) a United States
federal or state court of competent jurisdiction or United States federal or
state governmental, regulatory or administrative agency or commission shall
have issued an order, decree or ruling or taken any other action permanently
restraining, enjoining or otherwise prohibiting the transactions contemplated
by this Agreement and such order, decree, ruling or other action shall have
become final and non-appealable, provided that the party seeking to terminate
this Agreement pursuant to this clause (v) shall have used all reasonable
efforts to remove such order, decree, ruling or injunction, or (vi) any of the
conditions set forth in Article VIII shall not have been satisfied, and
provided, in the case of a termination pursuant to clause (i) or (vi) above,
that the terminating party shall not have breached in any material respect its
obligations under this Agreement in any manner that shall have proximately
contributed to the occurrence of the failure referred to in said clause. AIP
and RELP each shall (i) deliver its Disclosure Letter to one another not later
than 5:00 P.M., Central Time, September 20, 1997, and (ii) shall complete its
due diligence investigations not later than 5:00 P.M., Central Time, on
September 30, 1997.  Until October 7, 1997 (the period from the date of this
Agreement through October 7, 1997 being hereinafter referred to as the "Due
Diligence Period"), either party may terminate this Agreement without liability
or penalty due to the discovery of a fact or circumstance that reasonably could
be expected to constitute a Material Adverse Effect on the business, results of
operations or financial condition of the other party.  Unless objected to by
the party receiving the Disclosure Letter in writing prior to the expiration of
the Due Diligence Period, the receiving party shall be deemed to have approved
the other party's Disclosure Letter.

         9.3      Termination by RELP.  This Agreement may be terminated and
the Merger may be abandoned at any time prior to the Effective Time, before or
after the adoption and approval by the partners of RELP referred to in Section
8.1(a), by action of the General Partner, if (i) in the exercise of its good
faith judgment as to its fiduciary duties to its partners imposed by law, as
advised by counsel, the General Partner determines that such termination is
required by reason of a RELP Acquisition Proposal being made, (ii) the Board of
Trust Managers withdraws, materially modifies or changes in a manner materially
adverse to RELP its recommendations to AIP's shareholders of this Agreement or
the Merger, other than as a result of the occurrence of an event that in the
good faith judgment of the Board of Trust Managers has or is reasonably likely
to have a RELP Material Adverse Effect, (iii) the Board of Trust Managers
postpones the date scheduled for the meeting of shareholders of AIP to approve
this Agreement and the transactions contemplated hereby beyond March 31, 1998
or fails to set a date for such meeting by such date, except with the written
consent of RELP, (iv) there has been a breach by AIP of any representation or
warranty contained in this Agreement which would have or would be reasonably
likely to have an AIP Material Adverse Effect, which breach is not curable by
March 31,1998, or (v) there has been material breach of any of the covenants or
agreements set forth in this Agreement on the part of AIP, which breach is not
curable or, if curable, is not cured within 30 days after written notice of
such breach is given by RELP to AIP, or (vi) the condition set forth in Section
8.3(g) is not satisfied..

         9.4     Termination by AIP.  This Agreement may be terminated and the
Merger may be abandoned at any time prior to the Effective Time, before or
after the approval by the shareholders of AIP referred to in Section 8.1(a), by
action of the Board of Trust Managers,  if (i) in the exercise





                                       29
<PAGE>   30
of its good faith judgment as to its fiduciary duties to its shareholders
imposed by law, as advised by counsel, the Board of Trust Managers determines
that such termination is required by reason of an AIP Acquisition Proposal
being made, (ii) the General Partner withdraws, materially modifies or changes
in a manner materially adverse to AIP its recommendation to RELP's partners of
this Agreement or the Merger, other than as a result of the occurrence of an
event that in the good faith judgment of the General Partner has or is
reasonably likely to have an AIP Material Adverse Effect, (iii) the General
Partner postpones the date scheduled for the meeting of partners of RELP to
approve this Agreement and the transactions contemplated hereby beyond March
31, 1998, or fails to set a date for such meeting by such date, except with the
written consent of AIP, (iv) there has been a breach by RELP of any
representation or warranty contained in this Agreement which would have or
would be reasonably likely to have a RELP Material Adverse Effect, which breach
is not curable by March 31, 1998, or (v) there has been a material breach of
any of the covenants or agreements set forth in this Agreement on the part of
RELP, which breach is not curable or, if curable, is not cured within 30 days
after written notice of such breach is given by AIP to RELP.

         9.5.    Effect of Termination and Abandonment.  (a)  If an election to
terminate this Agreement is made pursuant to (i) Section 9.2(i) (except as a
result of a default or breach hereunder by AIP) or Section 9.2(ii), and a RELP
Acquisition Proposal relating to RELP shall have been made and, within one year
from the date of such termination, RELP consummates a RELP Acquisition Proposal
or enters into an agreement to consummate a RELP Acquisition Proposal which is
subsequently consummated, or (ii) Section 9.3(i), RELP shall pay to AIP,
provided that AIP was not in material breach of its obligations hereunder at
the time of such termination, as liquidated damages and not as a penalty or
forfeiture, an amount equal to the lesser of (m) $393,600 (the "Liquidated
Damages Amount") and (n) the sum of (1) the maximum amount that can be paid to
AIP without causing AIP to fail to meet the requirements of Sections 856(c)(2)
and (3) of the Code determined as if the payment of such amount did not
constitute income described in Sections 856(c)(2)(A)-(H) and 856(c)(3)(A)-(I)
of the Code ("Qualifying Income"), as determined by AIP's certified public
accountants, plus (2) an amount equal to the Liquidated Damages Amount less the
amount payable under clause (1) above in the event AIP receives a letter from
AIP's counsel indicating that AIP has received a ruling from the IRS to the
effect that Liquidated Damages Amount payments constitute Qualifying Income. In
addition to the Liquidated Damages Amount, AIP shall be entitled to receive
from RELP (or its successor in interest) all documented out-of-pocket costs and
expenses, up to a maximum of $196,800  in connection with this Agreement and
the transactions contemplated hereby (the "AIP Expenses") incurred by AIP. The
payments to which AIP is entitled under this Section 9.5(a) shall be its sole
remedy with respect to the termination of the Agreement under the circumstances
contemplated in this Section 9.5(a).

         (b)     If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.3(c) not
being satisfied), RELP shall, provided that AIP was not in material breach of
its obligations hereunder at the time of such termination, pay AIP for the AIP
Expenses, up to a maximum of $196,800, although it shall not be required to pay
the Liquidated Damages Amount, which payment of the AIP Expenses shall be AIP's
sole remedy for termination of the Agreement in such circumstances.





                                       30
<PAGE>   31
         (c)     If an election to terminate this Agreement is made pursuant to
(i) Section 9.2(i) (except as a result of a default or breach hereunder by
RELP) or Section 9.2(iii), and an AIP Acquisition Proposal relating to AIP
shall have been made and, within one year from the date of such termination,
AIP consummates an AIP Acquisition Proposal or enters into an agreement to
consummate an AIP Acquisition Proposal which is subsequently consummated, or
(ii) Section 9.4(i), AIP shall pay to RELP, provided that RELP was not in
material breach of its obligations hereunder at the time of such termination,
as liquidated damages and not as a penalty or forfeiture, an amount equal to
the Liquidated Damages Amount. In addition to the Liquidated Damages Amount,
RELP shall be entitled to receive from AIP (or its successor in interest) all
documented out-of-pocket costs and expenses, up to a maximum of $196,800, in
connection with this Agreement and the transactions contemplated hereby (the
"RELP Expenses" and, together with the AIP Expenses, the "Expenses")  incurred
by RELP. The payments to which RELP is entitled under this Section 9.5(c) shall
be its sole remedy with respect to the termination of the Agreement under the
circumstances contemplated in this Section 9.5(c)

         (d)     If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.2(c) not
being satisfied), AIP shall, provided that RELP was not in material breach of
its obligations hereunder at the time of such termination, pay RELP for the
RELP Expenses, up to a maximum of $196,800, although it shall not be required
to pay the Liquidated Damages Amount, which payment of the RELP Expenses shall
be RELP's sole remedy for termination of the Agreement in such circumstances.

         (e)     If this Agreement is terminated pursuant to Section 9.3(iv),
Section 9.3(v), Section 9.4(iv), or Section 9.4(v), the non-terminating party
shall, provided that the terminating party was not in material breach of its
obligations hereunder at the time of such termination, pay the terminating
party all Expenses, up to a maximum of $196,800, incurred by it and the
non-terminating party shall remain liable to the terminating party for its
breach.

         (f)      If either party terminates this Agreement during the Due
Diligence Period described in Section 9.2 above other than for a due diligence
related reason, the non-terminating party shall be entitled to receive the
Liquidated Damages Amount and the Expenses as provided in this Article IX.

         (g)     RELP agrees to amend this Section 9.5 at the request of AIP in
order to (x) maximize the portion of the Liquidated Damages Amount that may be
distributed to AIP hereunder without causing AIP to fail to meet the
requirements of Sections 856(c)(2) and (3) of the Code or (y) improve AIP's
chances of securing a favorable ruling described in this Section 9.5, provided
that no such amendment may result in any additional cost or expense to such
other party.

         (h)     In the event of termination of this Agreement and the
abandonment of the Merger pursuant to this Article IX, all obligations of the
parties hereto shall terminate, except the obligations of the parties pursuant
to this Section 9.5 and Section 7.10 and except for the provisions of Section
10.3, 10.4, 10.5, 10.6, 10.7, 10.9, 10.10, 10.13, 10.14 and 10.16. In the event
AIP or RELP has received the Liquidated Damages Amount, such recipient shall
not assert or pursue in any manner, directly or indirectly, any claim or cause
of action against the other party hereto or any of its officers, Trust
Managers, or  General Partners, as applicable, based in whole or part upon its
or their receipt, consideration, recommendation or approval of an Acquisition
Proposal or the exercise by AIP of its





                                       31
<PAGE>   32
right to termination under Section 9.4(i) or the exercise by RELP of its right
to termination under Section 9.3(i).  Notwithstanding the foregoing, in the
event AIP or RELP is required to file suit to seek all or a portion of such
Liquidated Damages Amount, and it ultimately succeeds, it shall be entitled to
all expenses, including attorney's fees and expenses, which it has incurred in
enforcing its right hereunder.

         (i)     If either party willfully fails to perform its duties and
obligations under this Agreement, the non- breaching party is additionally
entitled to all remedies available to it at law or in equity and to recover its
expenses from the breaching party.

         9.6     Extension; Waiver.  At any time prior to the Effective Time,
any party hereto, by action taken by its Board of Trust Managers or General
Partner, as applicable, may, to the extent legally allowed, (i) extend the time
for the performance of any of the obligations or other acts of the other
parties hereto, (ii) waive any inaccuracies in the representations and
warranties made to such party contained herein or in any document delivered
pursuant hereto and (iii) waive compliance with any of the agreements or
conditions for the benefit of such party contained herein. Any agreement on the
part of a party hereto to any such extension or waiver shall be valid only if
set forth in an instrument in writing signed on behalf of such party.

                         ARTICLE X.  GENERAL PROVISIONS

         10.1.   Nonsurvival of Representations, Warranties and Agreements.
All representations, warranties and agreements in this Agreement or in any
instrument delivered pursuant to this Agreement shall not survive the Merger;
provided, however, that the agreements contained in Article IV, the last
sentence of Section 7.4 and Sections 7.10, 7.11, 7.12, 7.13, 7.14, 7.15 and
7.16 and this Article X shall survive the Merger.

         10.2.   Notices.  Any notice required to be given hereunder shall be
in writing and shall be sent by facsimile transmission (confirmed by any of the
methods that follow), courier service (with proof of service), hand delivery or
certified or registered mail (return receipt requested and first-class postage
prepaid) and addressed as follows:

         If to AIP:
         American Industrial Properties REIT
         6220 N. Beltline Road, Suite 205
         Irving, Texas 75063
         Attention: Charles W. Wolcott, President
         Telecopy: (972) 550-6037

         If to RELP:
         USAA Real Estate Company
         8000 I-H 10 West, Suite 600
         San Antonio, Texas 78230
         Attention: Patrick Duncan, Senior Vice-President
         Telecopy: (210) 498-6214





                                       32
<PAGE>   33
or to such other address as any party shall specify by written notice so given,
and such notice shall be deemed to have been delivered as of the date so
delivered.

         10.3.   Assignment; Binding Effect; Benefit.  Neither this Agreement
nor any of the rights, interests or obligations hereunder shall be assigned by
any of the parties hereto (whether by operation of law or otherwise) without
the prior written consent of the other parties. Subject to the preceding
sentence, this Agreement shall be binding upon and shall inure to the benefit
of the parties hereto and their respective successors and assigns.
Notwithstanding anything contained in this Agreement to the contrary, except as
provided in the following sentence, nothing in this Agreement, expressed or
implied, is intended to confer on any person other than the parties hereto or
their respective heirs, successors, executors, administrators and assigns any
rights, remedies, obligations or liabilities under or by reason of this
Agreement. The provisions of Article IV and Sections 7.11, 7.12, 7.13, 7.14 and
7.15 (collectively, the "Third Party Provisions") shall benefit the persons
identified therein, but the aggregate liability of AIP with respect thereto
shall not exceed the amount specified in Article IX.

         10.4.   Entire Agreement.  This Agreement, the Exhibits, the RELP
Disclosure Letter, the AIP Disclosure Letter, the RELP Ancillary Agreements,
the AIP Ancillary Agreements and any documents delivered by the parties in
connection herewith constitute the entire agreement among the parties with
respect to the subject matter hereof and supersede all prior agreements and
understandings among the parties with respect thereto. No addition to or
modification of any provision of this Agreement shall be binding upon any party
hereto unless made in writing and signed by all parties hereto.

         10.5.   Confidentiality.  (a)  As used herein, "Confidential Material"
means, with respect to either party hereto (the "Providing Party"), all
information (written or oral) furnished (whether before or after the date
hereof) by the Providing Party and its directors, officers, employees,
affiliates or representatives of advisors, including counsel, lenders and
financial advisors (collectively, the "Providing Party Representatives") to the
other party hereto (the "Receiving Party") or such Receiving Party's directors,
officers, employees, affiliates or representatives of advisors, including
counsel, lenders and financial advisors or the Receiving Party's potential
sources of financing for the transactions contemplated by this Agreement
(collectively "the Receiving Party Representatives") and all analyses,
compilations, forecasts and other studies or other documents prepared by the
Providing Party or the Providing Party Representatives in connection with its
or their review of the transactions contemplated by this Agreement which
contain or reflect such information. The term "Confidential Material" does not
include, however, information which (i) at the time of disclosure or thereafter
is generally available to and known by the public other than as a result of a
disclosure directly or indirectly by the Receiving Party or the Receiving Party
Representatives in violation of this Agreement, (ii) at the time of disclosure
was available on a nonconfidential basis from a source other than the Providing
Party or the Providing Party Representatives, providing that such source is not
and was not bound by a confidentiality agreement with the Providing Party,
(iii) was known by the Receiving Party prior to receiving the Confidential
Material from the Providing Party or has been independently acquired or
developed by the Receiving Party without violating any of its obligations under
this Agreement, or (iv) is contained in any RELP Reports or AIP Reports or
Proxy Statement/Prospectus.





                                       33
<PAGE>   34
         (b)     Subject to paragraph (c) below or except as required by law,
the Confidential Material will be kept confidential and will not, without the
prior written consent of the Providing Party, be disclosed by the Receiving
Party or its Representatives, in whole or in part and will not be used by the
Receiving Party or its Representatives, directly or indirectly, for any purpose
other than in connection with this Agreement, the Merger or the evaluating,
negotiating or advising with respect to a transaction contemplated herein.
Moreover, each Receiving Party agrees to transmit Confidential Material to its
Representatives only if and to the extent that such Representatives need to
know the Confidential Material for purposes of such transaction and are
informed by such Receiving Party of the confidential nature of the Confidential
Material and of the terms of this Section.

         (c)     In the event that either Receiving Party, its Representatives
or anyone to whom such Receiving Party or its Representatives supply the
Confidential Material, are requested or required (by oral questions,
interrogatories, requests for information or documents, subpoena, civil
investigative demand, any informal or formal investigation by any government or
governmental agency or authority or otherwise in connection with legal
processes) to disclose any Confidential Material, such Receiving Party agrees
(i) to immediately notify the Providing Party of the existence, terms and
circumstances surrounding such a request, (ii) to consult with the Providing
Party on the advisability of taking legally available steps to resist or narrow
such request and (iii) if disclosure of such information is required, to
furnish only that portion of the Confidential Material which, in the opinion of
such Receiving Party's counsel, such Receiving Party is legally compelled to
disclose and to cooperate with any action by the Providing Party to obtain an
appropriate protective order or otherwise reliable assurances that confidential
treatment will be accorded the Confidential Material (it being agreed that the
Providing Party shall reimburse the Receiving Party for all reasonable
out-of-pocket expenses incurred by the Receiving Party in connection with such
cooperation).

         (d)     In the event of the termination of this Agreement in
accordance with its terms, promptly upon request from either Providing Party,
the Receiving Party shall, except to the extent prevented by law, redeliver to
the Providing Party or destroy all tangible Confidential Material and will not
retain any copies, extracts or other reproductions thereof in whole or in part.
Any such destruction shall be certified in writing to the Providing Party by an
authorized officer of the Receiving Party supervising the same. Notwithstanding
the foregoing, each Receiving Party and one Representative designated by each
Receiving Party shall be permitted to retain one permanent file copy of each
document constituting Confidential Material.

         (e)     Each party hereto further agrees that if this Agreement is
terminated in accordance with its terms, until one year from the date of
termination, (1) it will not offer to hire or hire any person currently or
formerly employed by the other party with whom such party has had contact prior
hereto other than persons whose employment shall have been terminated by such
other party prior to the date of such offer to hire or hiring and (2) neither
it nor its affiliates shall directly or indirectly, (a) (w) solicit, seek or
offer to effect or effect, (x) negotiate with or provide any information to the
Board of Trust Managers or General Partner, as applicable, of the other party,
or officer of the other party or any shareholder or partner, as applicable, of
the other party with respect to, (y) make any statement or proposal, whether
written or oral, either alone or in concert with others, to the Board of Trust
Managers or Board of Directors of the General Partner of the other party, any
director, Trust Manager or officer of the other party or any shareholder or
partner of the other party or any other person with respect to, or (z) make any
public announcement (except as required by law in respect





                                       34
<PAGE>   35
of actions permitted hereby) or proposal or offer whatsoever (including, but
not limited to, any "solicitation"of "proxies"as such terms are defined or used
in Regulation 14A of the Exchange Act) with respect to, (i) any form of
business combination or similar or other extraordinary transaction involving
the other party or any affiliate thereof, including, without limitation, a
merger, tender or exchange offer or liquidation of the other party's assets,
(ii) any form of restructuring, recapitalization or similar transaction with
respect to the other party or any affiliate thereto, (iii) any purchase of any
securities or assets, or rights or options to acquire any securities or assets
(through purchase, exchange, conversion or otherwise), of the other party or
any affiliate thereof, (iv) any proposal to seek representation on the Board of
Trust Managers or the Board of Directors of the General Partner, as
applicable, or otherwise to seek to control or influence the management, Board
of Trust Managers or the Board of Directors of the General Partner, as
applicable, or policies of the other party or any affiliate thereof, (v) any
request or proposal to waive, terminate or amend the provisions of this Section
10.5 or (vi) any proposal or other statement inconsistent with the terms of
this Section 10.5 or (b) instigate, encourage, join, act in concert with or
assist (including, but not limited to, providing or assisting in any way in the
obtaining of financing for, or acting as a joint or co-bidder for the other
party with) any third party to do any of the foregoing, unless and until such
party has received the prior written invitation or approval of a majority of
the Board of Trust Managers or the General Partner, as applicable, to do any of
the foregoing; provided that without such invitation or approval, either party
may at any time, on a confidential non-public basis, submit to the Chief
Executive Officer of AIP or the General Partner, as applicable, a proposal to
(a) amend any of the provisions of this Section 10.5(e) or (b) effect a
business combination or other extraordinary transaction with the other party
providing for the acquisition of all or substantially all of the assets or the
securities of the other party, including, without limitation, a merger, tender
offer or exchange offer. Each party hereto agrees that it will not agree with
any third party to waive its rights under this Section 10.5.

         10.6.   Amendment.  This Agreement may be amended by the parties
hereto, by action taken by the Board of Trust Managers or the Board of
Directors of the General Partner, as applicable, at any time before or after
approval of this Agreement or any other matter presented in connection with the
Merger by the shareholders of AIP and partners of RELP, but after any such
approval, no amendment shall be made which by law requires the further approval
of shareholders or partners, as applicable, without obtaining such further
approval. This Agreement may not be amended except by an instrument in writing
signed on behalf of each of the parties hereto.

         10.7.   Governing Law.  This Agreement shall be governed by and
construed in accordance with the laws of the State of Texas without regard to
its rules of conflict of laws. Each of AIP and RELP hereby irrevocably and
unconditionally consents to submit to the exclusive jurisdiction of the courts
of the State of Texas and of the United States District Court, Northern
District of Texas (the "Texas Courts") for any litigation arising out of or
relating to this Agreement and the transactions contemplated hereby (and agrees
not to commence any litigation relating thereto except in such courts), waives
any objection to the laying of venue of any such litigation in the Texas Courts
and agrees not to plead or claim in any Texas Court that such litigation
brought therein has been brought in an inconvenient forum.





                                       35
<PAGE>   36
         10.8.   Counterparts.  This Agreement may be executed by the parties
hereto in separate counterparts, each of which when so executed and delivered
shall be an original, but all such counterparts shall together constitute one
and the same instrument. Each counterpart may consist of a number of copies
hereof each signed by less than all, but together signed by all of the parties
hereto.

         10.9.   Headings.  Heading of the Articles and Sections of this
Agreement are for the convenience of the parties only and shall be given no
substantive or interpretive effect whatsoever.

         10.10.  Interpretation.  In this Agreement, unless the context
otherwise requires, words describing the singular number shall include the
plural and vice versa, and words denoting any gender shall include all genders
and words denoting natural persons shall include corporations and partnerships
and vice versa.

         10.11.  Waivers.  Except as provided in this Agreement, no action
taken pursuant to this Agreement, including, without limitation, any
investigation by or on behalf of any party, shall be deemed to constitute a
waiver by the party taking such action of compliance with any representations,
warranties, covenants or agreements contained in this Agreement. The waiver by
any party hereto of a breach of any provision hereunder shall not operate or be
construed as a waiver of any prior or subsequent breach of the same or any
other provision hereunder.

         10.12.  Incorporation.  The RELP Disclosure Letter and the AIP
Disclosure Letter and all Exhibits and Schedules attached hereto and thereto
and referred to herein and therein are hereby incorporated herein and made a
part hereof for all purposes as if fully set forth herein.

         10.13.  Severability.    If any provision of this Agreement is held to
be illegal, invalid or unenforceable under any current or future law, and if
the rights or obligations of the parties under this Agreement would not be
materially and adversely affected thereby, such provision shall be fully
separable, and this Agreement shall be construed and enforced as if such
illegal, invalid or unenforceable provision had never comprised a part thereof,
and the remaining provisions of this Agreement shall remain in full force and
effect and shall not be affected by the illegal, invalid or unenforceable
provision or by its severance therefrom.  In lieu of such illegal, invalid or
unenforceable provision, there shall be added automatically as a part of this
Agreement, a legal, valid and enforceable provision as similar in terms to such
illegal, invalid or unenforceable provision as may be possible, and the parties
hereto request the court or any arbitrator to whom disputes relating to this
Agreement are submitted to reform the otherwise illegal, invalid or
unenforceable provision in accordance with this Section 10.13.

         10.14.  Enforcement of Agreement.  The parties hereto agree that
irreparable damage would occur in the event that any of the provisions of this
Agreement was not performed in accordance with its specific terms or was
otherwise breached. It is accordingly agreed that the parties shall be entitled
to an injunction or injunctions to prevent breaches of this Agreement and to
enforce specifically the terms and provisions hereof in any Texas Court, this
being in addition to any other remedy to which they are entitled at law or in
equity.





                                       36
<PAGE>   37
         10.15.  Subsidiaries.  As used in this Agreement, the word
"Subsidiary" when used with respect to any party means any corporation,
partnership, joint venture, business trust or other entity, of which such party
directly or indirectly owns or controls at least a majority of the securities
or other interests having by their terms ordinary voting power to elect a
majority of the board of directors or others performing similar functions with
respect to such corporation or other organization.

         10.16.  Non-Recourse.  Neither the officers, Trust Managers nor
shareholders of AIP shall be personally bound or have any personal liability
hereunder. RELP shall look solely to the assets of AIP for satisfaction of any
liability of AIP with respect to this Agreement and the Ancillary Agreements to
which it is a party. RELP will not seek recourse or commence any action against
any of the shareholders of AIP or any of their personal assets, and will not
commence any action for money judgments against any of the Trust Managers or
officers of AIP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of AIP hereunder or thereunder. The
partners of RELP shall not be personally bound or have any personal liability
hereunder. AIP shall look solely to the assets of RELP for satisfaction of any
liability of RELP with respect to this Agreement and the Ancillary Agreements
to which it is a party. AIP will not seek recourse or commence any action
against any of the partners of RELP or any of their personal assets, and will
not commence any action for money judgments against any of the directors or
officers of RELP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of RELP hereunder or thereunder.

         IN WITNESS WHEREOF, the parties have executed this Agreement and
caused the same to be duly delivered on their behalf on the day and year first
written above.

                                   AMERICAN INDUSTRIAL PROPERTIES REIT


                                   /s/ Charles W. Wolcott                      
                                   -------------------------------------
                                   Charles W. Wolcott, President and
                                   Chief Executive Officer


                                   USAA REAL ESTATE INCOME INVESTMENTS I,
                                   A CALIFORNIA LIMITED PARTNERSHIP

                                   By:      USAA Investors I, Inc., Its General
                                            Partner                            
                                                                               
                                                                               
                                                                               
                                   /s/ T. Patrick Duncan                       
                                   --------------------------------------      
                                   T. Patrick Duncan                           
                                   Senior Vice President - Operations          





                                       37

<PAGE>   1





                                                                     EXHIBIT 2.2

                              AMENDED AND RESTATED
                          AGREEMENT AND PLAN OF MERGER


       THIS AMENDED AND RESTATED AGREEMENT AND PLAN OF MERGER (this
"Agreement"), dated as of June 30, 1997, is entered into by and between
American Industrial Properties REIT, a Texas real estate investment trust
("AIP") , and USAA Real Estate Income Investments II Limited Partnership, a
Texas limited partnership ("RELP").  USAA Real Estate Company, a Delaware
corporation ("Realco"), is a party to this Agreement solely for the purpose of
binding itself to the provisions of Section 7.10 hereunder.

                                    RECITALS

       A.     The Board of Trust Managers of AIP (the "Board of Trust
Managers") and the general partner of RELP have each determined that a business
combination between AIP and RELP is in the best interests of their shareholders
and partners, respectively, and presents an opportunity for their respective
businesses to achieve strategic and financial benefits, and accordingly have
agreed to effect a merger subject to the terms and conditions set forth herein.


       B.     AIP and RELP desire to make certain representations, warranties
and agreements in connection with the merger.

       NOW, THEREFORE, in consideration of the foregoing, and of the
representations, warranties, covenants and agreements contained herein, AIP and
RELP hereby agree as follows:

                             ARTICLE I.  THE MERGER

       1.1.   The Merger. Subject to the terms and conditions of this
Agreement, at the Effective Time (as defined in Section 1.3), RELP shall be
merged with and into AIP in accordance with this Agreement and the Plan of
Merger (the "Plan of Merger") in substantially the form attached hereto as
Exhibit A, with such completions, additions and substitutions conforming to the
terms of this Agreement as the parties shall approve, such approval to be
conclusively evidenced by their causing the Plan of Merger containing such
completions, additions or substitutions to be filed in accordance with
applicable laws; and the separate existence of RELP shall thereupon cease (the
"Merger"). AIP shall be the surviving entity in the Merger (sometimes
hereinafter referred to as the "Survivor").  The Merger shall have the effects
specified in Section 23.60  of the Texas Real Estate Investment Trust Act, as
amended (the "Texas REIT Act") and Section 2.11 of the Texas Revised Limited
Partnership Act (the "LP Act").

       1.2.   The Closing. Subject to the terms and conditions of this
Agreement, the closing of the Merger (the "Closing") shall take place at the
offices of Liddell, Sapp, Zivley, Hill & LaBoon, L.L.P. ("Liddell, Sapp"),
located at 2200 Ross Avenue, Suite 900, Dallas, Texas at 10:00 a.m., local
time, within five business days after receipt of approval of the Merger by
AIP's shareholders and RELP's partners, or at such other time, date or place as
AIP and RELP may agree. The date on which the Closing occurs is hereinafter
referred to as the "Closing Date."
<PAGE>   2
       1.3.   Effective Time. If all the conditions to the Merger set forth in
Article VIII shall have been fulfilled or waived (and this Agreement shall not
have been terminated as provided in Article IX), AIP and RELP shall cause
Articles of Merger satisfying the requirements of the Texas REIT Act and
Articles of Merger satisfying the requirements of the LP Act to be properly
executed, verified and delivered for filing in accordance with the LP Act and
the Texas REIT Act on the Closing Date. The Merger shall become effective for
accounting and all other purposes to the fullest extent permitted by law as of
the close of business on December 31, 1997 (the "Effective Time") or such other
date as may be agreed to by the parties. For state law purposes, the Merger
shall become effective upon the issuance of a certificate of merger by the
Secretary of State of the State of Texas in accordance with the LP Act or at
such later time which AIP and RELP shall have agreed upon and designated in
such filings in accordance with applicable law.

                       ARTICLE II.  DECLARATION OF TRUST
                           AND BYLAWS OF THE SURVIVOR

       2.1.   Declaration of Trust.  The Declaration of Trust of AIP  in effect
immediately prior to the Effective Time shall be the Declaration of Trust of
the Survivor until duly amended in accordance with applicable law.

       2.2.   Bylaws.  The Bylaws of AIP in effect immediately prior to the
Effective Time shall be the Bylaws of the Survivor until duly amended in
accordance with applicable law.

                ARTICLE III.  TRUST MANAGERS AND OFFICERS OF AIP

       3.1.   Trust Managers.  The Trust Managers of AIP immediately prior to
the Effective Time shall be the Trust Managers of AIP as of the Effective Time.


       3.2.    Officers.  The officers of AIP immediately prior to the
Effective Time shall be the officers of AIP as of the Effective Time.

                    ARTICLE IV.  RELP PARTNERSHIP  INTERESTS

       4.1.   Conversion of the RELP Partnership Interest.  (a)   At the
Effective Time, each Common Share of Beneficial Interest of AIP outstanding
immediately prior to the Effective Time shall remain outstanding and shall
represent one Common Share of Beneficial Interest of AIP.

       (b)    At the Effective Time, the general and limited partnership
interests of RELP  (each a  "RELP Interest"), issued and outstanding
immediately prior to the Effective Time shall, by virtue of the Merger and
without any action on the part of holder thereof, be converted into the right
to receive Common Shares of Beneficial Interest, $0.10 par value per share (the
"AIP Common Shares"), of AIP.  The aggregate number of AIP Common Shares to be
issued to the RELP partners in connection with the Merger shall be equal to
$10,200,000 (the "Purchase Price") divided by the Share Price (the "Total
Shares").  If, during the period from the date hereof to and including the
Closing Date, (i) the RELP pays any mortgage indebtedness existing on the date
hereof or (ii) the outstanding AIP Common Shares shall have been changed to a
different number of shares by reason of any share dividend, subdivision,
reclassification, recapitalization, share split, reverse share split,

                                      2
<PAGE>   3
combination, exchange of shares or the like, the Purchase Price shall be
appropriately adjusted.  The term "Share Price" shall mean $2.625.  The number
of AIP Common Shares to be received by a partner shall be equal to the Total
Shares multiplied by such partner's percentage interest in RELP plus each
limited partner's pro rata portion of the general partnership interest of the
RELP's general partner.

       (c)    As a result of the Merger and without any action on the part of
the holder thereof, at the Effective Time,  all RELP Interests  shall cease to
be outstanding and shall be canceled and retired, and each holder of a RELP
Interest shall thereafter cease to have any rights with respect to such RELP
Interest, except the right to receive, without interest, the AIP Common Shares
and cash for fractional shares of AIP Common Shares in accordance with Sections
4.1(b) and 4.2(e).

       4.2.   Exchange of RELP Interests.  (a)  As of the Effective Time, AIP
shall deposit, or shall cause to be deposited, with an exchange agent selected
by AIP, which shall be AIP's Transfer Agent or such other party reasonably
satisfactory to RELP (the "Exchange Agent"), for the benefit of the holders of
RELP Interests, for exchange in accordance with this Article IV, certificates
representing the Total Shares and the cash in lieu of fractional shares (such
cash and certificates for the Total Shares together with any dividends or
distributions with respect thereto, being hereinafter referred to as the
"Exchange Fund") to be issued pursuant to Section 4.1 and paid pursuant to this
Section 4.2 in exchange for outstanding RELP Interests.

       (b)    Promptly after the Effective Time, AIP shall cause the Exchange
Agent to mail to each holder of record of a RELP Interest (x) a certificate
representing the number of whole shares of AIP Common Shares and (y) a check
representing the amount of cash in lieu of fractional shares, if any, and
unpaid dividends and distributions, if any, which such holder has the right to
receive in respect of the RELP Interest surrendered pursuant to the provisions
of this Article IV, after giving effect to any required withholding tax.  No
interest will be paid or accrued on the cash in lieu of fractional shares and
unpaid dividends and distributions, if any, payable to holders of RELP
Interests.  In the event of a transfer of ownership of RELP Interests which is
not registered in the transfer records of RELP, a certificate representing the
proper number of AIP Common Shares, together with a check for the cash to be
paid in lieu of fractional shares, may be issued to such a transferee if such
holder presents to the Exchange Agent, all documents required to evidence and
effect such transfer and to evidence that any applicable transfer taxes have
been paid.

       (c)    At and after the Effective Time, there shall be no transfers on
the transfer books of RELP of RELP Interests which were outstanding immediately
prior to the Effective Time.

       (d)    No fractional AIP Common Shares shall be issued pursuant hereto.
In lieu of the issuance of any fractional AIP Common Shares pursuant to Section
4.1(b), cash adjustments will be paid to holders in respect of any fractional
AIP Common Shares that would otherwise be issuable, and the amount of such cash
adjustment shall be equal to such fractional proportion of the Share Price.

       (e)    Any portion of the Exchange Fund (including the proceeds of any
investments thereof and any AIP Common Shares) that remains unclaimed by the
former partners of RELP one year after the Effective Time shall be delivered to
AIP. Any former partners of RELP who have not theretofore





                                       3
<PAGE>   4
complied with this Article IV shall thereafter look only to AIP for delivery of
their AIP Common Shares, and payment of cash in lieu of fractional shares and
unpaid dividends and distributions on the AIP Common Shares deliverable in
respect of each RELP Interest such partners hold as determined pursuant to this
Agreement, in each case, without any interest thereon.

       (f)    None of AIP, RELP, the Exchange Agent or any other person shall
be liable to any former holder of RELP Interests for any amount properly
delivered to a public official pursuant to applicable abandoned property,
escheat or similar laws.


               ARTICLE V.  REPRESENTATIONS AND WARRANTIES OF RELP

       RELP represents and warrants to AIP as set forth below. As contemplated
below, a "RELP Disclosure Letter" will be delivered to AIP on or before
September 20, 1997.  The RELP Disclosure Letter shall provide the information
or exceptions described below and shall list all of the assets of the RELP that
will not be transferred in connection with the Merger. The RELP Disclosure
Letter shall be amended prior to Closing to cause such representations and
warranties to be materially true and correct on the Closing Date, but RELP
shall remain liable for any material breach of such representations and
warranties reflected in such amendment only as provided in Section 9.5(d),
below.

       5.1.   Existence; Good Standing; Authority; Compliance with Law.  (a)
RELP is a limited partnership,  duly formed, validly existing and in good
standing under the laws of the State of Texas.  To its actual knowledge, RELP
is duly licensed or qualified to do business as a foreign limited partnership
and is in good standing under the laws of any other state of the United States
in which the character of the properties owned or leased by it therein or in
which the transaction of its business makes such qualification necessary,
except where the failure to be so qualified would not have a material adverse
effect on the business, results of operations or financial condition of RELP (a
"RELP Material Adverse Effect"). RELP has all requisite power and authority to
own, operate, lease and encumber its properties and carry on its business as
now conducted.

       (b)     To the RELP's actual knowledge, it is not in violation of any
order of any court, governmental authority or arbitration board or tribunal, or
any law, ordinance, governmental rule or regulation to which RELP or any of its
properties or assets is subject, where such violation would have a RELP
Material Adverse Effect. RELP has obtained all licenses, permits and other
authorizations and has taken all actions required by applicable law or
governmental regulations in connection with its business as now conducted,
where the failure to obtain any such item or to take any such action would have
a RELP Material Adverse Effect. A copy of RELP's Agreement of Limited
Partnership and Certificate of Limited Partnership (collectively, the "RELP
Organizational Documents") have been delivered or made available to AIP and its
counsel and such documents will be listed in the RELP Disclosure Letter and
were or will be true and correct when delivered or made available.

       5.2.   Authorization, Validity and Effect of Agreements.  RELP has the
requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions





                                       4
<PAGE>   5
contemplated by this Agreement (the "RELP Ancillary Agreements"). Subject only
to the approval of this Agreement and the transactions contemplated hereby in
accordance with the Agreement of Limited Partnership of the RELP, the
consummation by RELP of this Agreement, the RELP Ancillary Agreements and the
transactions contemplated hereby have been duly authorized by all requisite
action on the part of RELP. In reliance upon the legal opinion described in
Section 8.2(e), RELP believes this Agreement constitutes, and the RELP
Ancillary Agreements (when executed and delivered pursuant hereto for value
received) will constitute, the valid and legally binding obligations of RELP,
enforceable against RELP in accordance with their respective terms, subject to
applicable bankruptcy, insolvency, moratorium or other similar laws relating to
creditors' rights and general principles of equity (collectively, "Equitable
Remedies").

       5.3.   Future Issuances.  To RELP's actual knowledge, there are not at
the date of this Agreement any existing options, warrants, calls,
subscriptions, convertible securities, or other rights, agreements or
commitments which obligate RELP to issue, transfer or sell any RELP Interests.
After the Effective Time, AIP will have no obligation to issue, transfer or
sell any RELP Interest.

       5.4.   Other Interests.  Except as set forth in the RELP Disclosure
Letter, RELP does not own directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

       5.5.   No Violation.  To RELP's actual knowledge, neither the execution
and delivery by RELP of this Agreement nor the consummation by RELP of the
transactions contemplated hereby in accordance with the terms hereof, will: (i)
conflict with or result in a breach of any provisions of the Agreement of
Limited Partnership of RELP; (ii) except as contemplated by the RELP Ancillary
Agreements or as will be set forth in the RELP Disclosure Letter, violate, or
conflict with, or result in a breach of any provision of, or constitute a
default (or an event which, with notice or lapse of time or both, would
constitute a default) under, or result in the termination or in a right of
termination or cancellation of, or accelerate the performance required by, or
result in the creation of any lien, security interest, charge or encumbrance
upon any of the properties of RELP under, or result in being declared void,
voidable or without further binding effect, any of the terms, conditions or
provisions of any note, bond, mortgage, indenture, deed of trust or any
license, franchise, permit, lease, contract, agreement or other instrument,
commitment or obligation to which RELP is a party, or by which RELP or any of
its  properties is bound or affected, except for any of the foregoing matters
which, individually or in the aggregate, would not have a RELP Material Adverse
Effect; or (iii) other than the filings provided for in Article I, any filings
required under the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), the Securities Act or applicable state securities and "Blue Sky" laws
(collectively, the "Regulatory Filings"), require any consent, approval or
authorization of, or declaration, filing or registration with, any domestic
governmental or regulatory authority, except where the failure to obtain any
such consent, approval or authorization of, or declaration, filing or
registration with, any governmental or regulatory authority would not have an
RELP Material Adverse Effect.

       5.6.   SEC Documents.  (a) RELP has made available or will make
available to AIP prior to September 30, 1997, each registration statement,
report, proxy statement or information statement and all exhibits thereto
prepared by it or relating to its properties (including registration statements





                                       5
<PAGE>   6
covering mortgage pass-through certificates) since January 1, 1994, each in the
form (including exhibits and any amendments thereto) filed with the SEC
(collectively, the "RELP Reports"). The RELP Reports, which were or will be
filed with the SEC in a timely manner, constitute all forms, reports and
documents required to be filed by RELP under the Securities Act of 1933, as
amended (the "Securities Act"), the Exchange Act and the rules and regulations
promulgated thereunder (collectively the "Securities Laws") for the periods
stated above.

       (b)    To the RELP's actual knowledge, as of their respective dates, the
RELP Reports (i) complied as to form in all material respects with the
applicable requirements of the Securities Laws and (ii) did not contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements made therein, in the
light of the circumstances under which they were made, not misleading. To the
RELP's actual knowledge, each of the balance sheets of RELP included in or
incorporated by reference into the RELP Reports (including the related notes
and schedules) fairly presents the financial position of RELP as of its date
and each of the consolidated statements of income, retained earnings and cash
flows of RELP included in or incorporated by reference into the RELP Reports
(including any related notes and schedules) fairly presents the results of
operations, retained earnings and cash flows, as the case may be, of RELP for
the periods set forth therein (subject, in the case of unaudited statements, to
normal year-end audit adjustments which would not be material in amount or
effect), in each case in accordance with generally accepted accounting
principles consistently applied during the periods involved, except as may be
noted therein and except, in the case of the unaudited statements, as permitted
by the Securities Laws.

       (c)    Except as and to the extent set forth on the balance sheet of
RELP at March 31, 1997, including all notes thereto, or as set forth in the
RELP Reports, RELP has no material liabilities or obligations of any nature
(whether accrued, absolute, contingent or otherwise) that would be required to
be reflected on, or reserved against in, a balance sheet of RELP or in the
notes thereto, prepared in accordance with generally accepted accounting
principles consistently applied, except liabilities arising in the ordinary
course of business since such date which would not have a RELP Material Adverse
Effect.

       5.7.   Litigation.  To the RELP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which RELP is a party or by which any of its
properties or assets are bound or to which USAA Investors II, Inc. (the
"General Partner")  or the General Partner's,  directors, officers, or
affiliates is a party or by which any of their properties or assets are bound,
and (ii) except as will be set forth in the RELP Disclosure Letter, no actions,
suits or proceedings pending against RELP or against the General Partner or the
General Partner's directors, officers or affiliates or, to the knowledge of the
General Partner, threatened against RELP or against the General Partner or the
General Partner's  directors, officers  or affiliates, at law or in equity, or
before or by any federal or state commission, board, bureau, agency or
instrumentality, that in the case of clauses (i) or (ii) above are reasonably
likely, individually or in the aggregate, to have a RELP Material Adverse
Effect.

       5.8.   Absence of Certain Changes.  Except as disclosed in the RELP
Reports filed prior to the date hereof, since March 31, 1997, (i) RELP
conducted its business only in the ordinary course of such business (which for
purposes of this section only, shall include all acquisitions of real estate





                                       6
<PAGE>   7
properties and financing arrangements made in connection therewith or otherwise
will be set forth in the RELP Disclosure Letter); (ii) there has not been any
RELP Material Adverse Effect; (iii) there has not been any distribution,
setting aside or payment of any distribution with respect to any RELP Interest,
and (iv) there has not been any material change in RELP's accounting
principles, practices or methods.

       5.9.   Taxes.  (a)  Except as may be set forth in the RELP Disclosure
Letter, RELP (i) has timely filed all federal, state and foreign tax returns
including, without limitation, information returns and reports required to be
filed by it for tax periods ended prior to the date of this Agreement or
requests for extensions have been timely filed and any such request has been
granted and has not expired and all such returns are accurate and complete in
all material respects, (ii) has paid or accrued all taxes shown to be due and
payable on such returns or which have become due and payable pursuant to any
assessment, deficiency notice, 30-day letter or other notice received by it and
(iii) has properly accrued all taxes for such periods and periods subsequent to
the periods covered by such returns. RELP has not received notice that the
federal, state and local income and franchise tax returns of RELP has been or
will be examined by any taxing authority. RELP has not executed or filed with
the Internal Revenue Service (the "IRS") or any other taxing authority any
agreement now in effect extending the period for assessment or collection of
any income or other taxes.

       (b)    Except as may be set forth in the RELP Disclosure Letter, RELP is
not  a party to any pending action or proceeding by any governmental authority
for assessment or collection of taxes, and no claim for assessment or
collection of taxes has been asserted against it. True, correct and complete
copies of all federal, state and local income or franchise tax returns filed by
RELP since January 1, 1991 and all communications relating thereto have been
delivered to AIP or made available to representatives of AIP or will be so
delivered or made available prior to September 30, 1997. RELP does not hold any
asset (i) the disposition of which could be subject to rules similar to Section
1374 of the Internal Revenue Code of 1986, as amended (the "Code") as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 5.9, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

       5.10.  Books and Records.  The books of account and other financial
records of RELP are in all material respects true, complete and correct, have
been maintained in accordance with good business practices, and are accurately
reflected in all material respects in the financial statements included in the
RELP Reports.

       5.11.  Properties.  (a)  RELP owns fee simple title to each of the real
properties reflected on the most recent balance sheet of RELP included in the
RELP Reports or as may be identified in the RELP Disclosure Letter (the "RELP
Properties"), which are all of the real estate properties owned by it,  free
and clear of liens, mortgages or deeds of trust, claims against title, charges
which are liens or security interests ("Encumbrances") except as will be noted
in the RELP Disclosure Letter. To RELP's actual knowledge, the RELP Properties
are not subject to any rights of way, written agreements, laws, ordinances and
regulations affecting building use or occupancy, or reservations of an interest
in title (collectively, "Property Restrictions"), except for (i) Encumbrances
and Property Restrictions that will be set forth in the RELP Disclosure Letter,
(ii) Property Restrictions imposed or promulgated by law or any governmental
body or authority with respect to real property, including





                                       7
<PAGE>   8
zoning regulations, provided they do not materially adversely affect the
current use of the property, (iii) Encumbrances and Property Restrictions
disclosed on existing title reports or current surveys (in either case copies
of which title reports and surveys have been or will be delivered or made
available to AIP September 30, 1997), (iv) mechanics', carriers', workmen's,
repairmen's liens and other Encumbrances, Property Restrictions and other
limitations of any kind, if any, which have heretofore been bonded (and that
will be listed in the RELP Disclosure Letter) or which individually or in the
aggregate do not exceed $100,000, do not materially detract from the value of
or materially interfere with the present use of any of the RELP Properties
subject thereto or affected thereby, and do not otherwise materially impair
business operations conducted by RELP and which have arisen or been incurred
only in its construction activities or in the ordinary course of business.

       (b)    Valid policies of title insurance have been issued insuring
either (a) RELP's fee simple title to the RELP Properties or (b) first mortgage
liens thereon, subject only to the matters disclosed above and as may be set
forth in the RELP Disclosure Letter, and such policies are, at the date hereof,
in full force and effect and no claim has been made against any such policy. To
RELP's actual knowledge, except as will be set forth in the RELP Disclosure
Letter: (i) there is no certificate, permit or license from any governmental
authority having jurisdiction over any of the RELP Properties or any agreement,
easement or other right which is necessary to permit the lawful use and
operation of the buildings and improvements on any of the RELP Properties or
which is necessary to permit the lawful use and operation of all driveways,
roads and other means of egress and ingress to and from any of the RELP
Properties that has not been obtained and is not in full force and effect, or
of any pending threat of modification or cancellation of any of same; (ii) RELP
has not received written notice of any material violation of any federal, state
or municipal law, ordinance, order, regulation or requirement affecting any
portion of any of the RELP Properties issued by any governmental authority;
(iii) there are no structural defects relating to the RELP Properties and no
RELP Properties whose building systems are not in working order in any material
respect; and (iv) there is (A) no physical damage to any RELP Property in
excess of $100,000 for which there is no insurance in effect covering the cost
of the restoration, (B) no current renovation to any RELP Property the cost of
which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any RELP Property, the cost of which exceeds $100,000.

       (c)    Except as will be set forth in the RELP Disclosure Letter, RELP
has not received notice to the effect that and there are no (A) condemnation or
rezoning proceedings that are pending or threatened with respect to any of the
RELP Properties or (B) zoning, building or similar laws, codes, ordinances,
orders or regulations that are or will be violated by the continued
maintenance, operation or use of any buildings or other improvements on any of
the RELP Properties or by the continued maintenance, operation or use of the
parking areas. All work to be performed, payments to be made and actions to be
taken by RELP prior to the date hereof pursuant to any agreement entered into
with a governmental body or authority in connection with a site approval,
zoning reclassification or other similar action relating to the RELP Properties
(e.g., Local Improvement District, Road Improvement District, Environmental
Mitigation) has been performed, paid or taken, as the case may be, and RELP is
not aware of any planned or proposed work, payments or actions that may be
required after the date hereof pursuant to such agreements, except as will be
set forth in the RELP Disclosure Letter.





                                       8
<PAGE>   9
       5.12.  Environmental Matters.  To RELP's actual knowledge, RELP has not
caused (i) the unlawful presence of any hazardous substances, hazardous
materials, toxic substances or waste materials (collectively, "Hazardous
Materials") on any of the RELP Properties, or (ii) any unlawful spills,
releases, discharges or disposal of Hazardous Materials to have occurred or be
presently occurring on or from the RELP Properties as a result of any
construction on or operation and use of such properties, which presence or
occurrence would, individually or in the aggregate, have a RELP Material
Adverse Effect; and in connection with the construction on or operation and use
of the RELP Properties, RELP has not failed to comply, in any material respect,
with any applicable local, state and federal environmental laws, regulations,
ordinances and administrative and judicial orders relating to the generation,
recycling, reuse, sale, storage, handling, transport and disposal of any
Hazardous Materials.

       5.13.  Labor Matters.  RELP is not a party to, or bound by, any
collective bargaining agreement, contract or other agreement or understanding
with a labor union or labor union organization. There is no unfair labor
practice or labor arbitration proceeding pending or, to the knowledge of the
General Partner, threatened against RELP relating to its business, except for
any such proceeding which would not have a RELP Material Adverse Effect. To the
knowledge of the General Partner, there are no organizational efforts with
respect to the formation of a collective bargaining unit presently being made
or threatened involving employees of RELP or any of its Subsidiaries.

       5.14.   No Brokers.  Except the fee that is to be paid to Houlihan Lokey
Howard & Zukin ("Houlihan")  by RELP as described in Section 5.15 below, RELP
has not entered into any contract, arrangement or understanding with any person
or firm which may result in the obligation of RELP or AIP to pay any finder's
fees, brokerage or agent's commissions or other like payments in connection
with the negotiations leading to this Agreement or the consummation of the
transactions contemplated hereby. RELP is not aware of any claim for payment of
any finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby.

       5.15.   Opinion of Financial Advisor.  RELP has retained Houlihan to
review the transaction contemplated by this Agreement and to issue an opinion
to the effect that, as of the date of such opinion, the Purchase Price is fair
to the holders of RELP Interests from a financial point of view.

       5.16.   Related Party Transactions.  Except as set forth in the RELP
Disclosure Letter, there are no arrangements, agreements or contracts entered
into by RELP with (i) any consultant, (ii) any person who is an officer,
director or affiliate of RELP or its General Partner, any relative of any of
the foregoing or any entity of which any of the foregoing is an affiliate, or
(iii) any person who acquired RELP Interests in a private placement.

       5.17.   Contracts and Commitments.  The RELP Disclosure Letter will set
forth (i) all unsecured notes or other obligations of RELP which individually
may result in total payments in excess of $100,000, (ii) all notes, debentures,
bonds and other evidence of indebtedness which are secured or collateralized by
mortgages, deeds of trust or other security interests in the RELP Properties or
personal property of RELP,  and (iii) each commitment entered into by RELP
which may result in total payments or liability in excess of $100,000. Copies
of the foregoing will be





                                       9
<PAGE>   10
delivered or made available to AIP prior to September 30, 1997, will be listed
on the RELP Disclosure Letter and will be materially true and correct when
delivered or made available. RELP has not received any notice of a default that
has not been cured under any of the documents described in clause (i) above or
is in default respecting any payment obligations thereunder beyond any
applicable grace periods. All options of RELP to purchase real property will be
set forth on the RELP Disclosure Letter and such options and RELP's rights
thereunder are in full force and effect. All joint venture agreements to which
RELP is a party will be set forth on the RELP Disclosure Letter and RELP is not
in default with respect to any obligations, which individually or in the
aggregate are material, thereunder.

       5.18.   Development Rights.  Set forth in the RELP Disclosure Letter
will be a list of all material agreements entered into by RELP relating to the
development, rehabilitation, capital improvement or construction of office
buildings, industrial facilities  or other real estate properties, which
development or construction has not been substantially completed as of the date
of this Agreement. Such agreements, true and correct copies of all of which
will be delivered or made available to AIP prior to September 30, 1997, will be
listed in the RELP Disclosure Letter, have not been modified and are valid and
binding in accordance with their respective terms.

       5.19.   Convertible Securities.  To RELP's actual knowledge, RELP has no
outstanding options, warrants or other securities exercisable for, or
convertible into, RELP Interests, the terms of which would require any anti-
dilution adjustments by reason of the consummation of the transactions
contemplated hereby.

              ARTICLE VI .  REPRESENTATIONS AND WARRANTIES OF AIP

       AIP represents and warrants to RELP as set forth below.  As contemplated
below, an "AIP Disclosure Letter" will be delivered to RELP on or before
September 20, 1997.  The AIP Disclosure Letter shall provide the information or
exceptions described below. The AIP Disclosure Letter shall be amended prior to
Closing to cause such representations and warranties to be materially true and
correct on the Closing Date, but AIP shall remain liable for any material
breach of such representations and warranties reflected in such amendment only
as provided in Section 9.5(d), below.

       6.1.    Existence; Good Standing; Authority; Compliance with Law.  (a)
AIP is a real estate investment trust duly organized and  validly existing
under the laws of the State of Texas.   To AIP's actual knowledge, AIP is duly
licensed or qualified to do business and is in good standing under the laws of
any other state of the United States in which the character of the properties
owned or leased by it therein or in which the transaction of its business makes
such qualification necessary, except where the failure to be so qualified would
not have a material adverse effect on the business, results of operations or
financial condition of AIP and its subsidiaries taken as a whole (an "AIP
Material Adverse Effect"). AIP has all requisite power and authority to own,
operate, lease and encumber its properties and carry on its business as now
conducted. Each of AIP's Subsidiaries is a corporation,





                                       10
<PAGE>   11
limited liability company or partnership duly organized, validly existing and
in good standing under the laws of its jurisdiction of incorporation or
organization, has the requisite power and authority to own its properties and
to carry on its business as it is now being conducted, and is duly qualified to
do business and is in good standing in each jurisdiction in which the ownership
of its property or the conduct of its business requires such qualification,
except for jurisdictions in which such failure to be so qualified or to be in
good standing would not have an AIP Material Adverse Effect.

       (b)    To AIP's actual acknowledge, neither AIP nor any AIP Subsidiary
is in violation of any order of any court, governmental authority or
arbitration board or tribunal, or any law, ordinance, governmental rule or
regulation to which AIP or any AIP Subsidiary or any of their respective
properties or assets is subject, where such violation would have an AIP
Material Adverse Effect. AIP and its Subsidiaries have obtained all licenses,
permits and other authorizations and have taken all actions required by
applicable law or governmental regulations in connection with their business as
now conducted, where the failure to obtain any such item or to take any such
action would have an AIP Material Adverse Effect. Copies of AIP's and its
Subsidiaries' Declaration of Trust, Articles of Incorporation, Bylaws,
organizational documents and partnership and joint venture agreements have been
or will be prior to September 30, 1997, delivered or made available to RELP and
such documents will be listed in the AIP Disclosure Letter and were or will be
true and correct when delivered or made available. For the purposes of the
immediately preceding sentence, the term "Subsidiary"shall include the entities
set forth in the AIP Disclosure Letter, which are all of AIP's Subsidiaries.

       6.2.    Authorization, Validity and Effect of Agreements.  AIP has the
requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions contemplated by this
Agreement to which it is a party (the "AIP Ancillary Agreements"). Subject only
to the approval of the issuance of AIP Common Shares pursuant to the Merger
contemplated hereby by the holders of two-thirds of the outstanding AIP Common
Shares, present and voting thereon, the consummation by AIP of this Agreement,
the AIP Ancillary Agreements and the transactions contemplated hereby have been
duly authorized by all requisite action on the part of AIP. This Agreement
constitutes, and the AIP Ancillary Agreements (when executed and delivered
pursuant hereto for value received) will constitute, the valid and legally
binding obligations of AIP enforceable against AIP in accordance with their
respective terms, subject to Equitable Remedies.

       6.3.    Capitalization.  On June 15, 1997, the authorized capital stock
of AIP consists of 10,000,000 Common Shares. As of the date hereof, all
10,000,000 Common Shares are outstanding. AIP has no outstanding bonds,
debentures, notes or other obligations (other than to Realco), the holders of
which have the right to vote (or which are convertible into or exercisable for
securities having the right to vote) with the shareholders of AIP on any
matter. Except as set forth in the AIP Disclosure Letter, all such issued and
outstanding of AIP Common Shares are duly authorized, validly issued, fully
paid, nonassessable and free of preemptive rights. Except as set forth in the
AIP Disclosure Letter, there are not at the date of this Agreement any existing
options, warrants, calls,





                                       11
<PAGE>   12
subscriptions, convertible securities, or other rights, agreements or
commitments which obligate AIP or any of its Subsidiaries to issue, transfer or
sell any shares or other equity interest of AIP or any of its Subsidiaries
except under any employee incentive plan approved by AIP's shareholders. There
are no agreements or understandings to which AIP is a party with respect to the
voting of any AIP Common Shares or which restrict the transfer of any such
shares, except in order to protect its REIT status.

       6.4.   Subsidiaries.  Except as set forth in the AIP Disclosure Letter,
AIP owns directly or indirectly each of the outstanding shares of capital stock
or all of the partnership or other equity interests of each of AIP's
Subsidiaries free and clear of all liens, pledges, security interests, claims
or other encumbrances other than liens imposed by local law which are not
material.

       6.5.   Other Interests.   Except as will be disclosed in the AIP
Disclosure Letter and except for interests in the AIP Subsidiaries, neither AIP
nor any AIP Subsidiary owns directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

       6.6.   No Violation.   Neither the execution and delivery by AIP of this
Agreement nor the consummation by AIP of the transactions contemplated hereby
in accordance with the terms hereof, will: (i) conflict with or result in a
breach of any provisions of AIP's Declaration of Trust; (ii) violate, or
conflict with, or result in a breach of any provision of, or constitute a
default (or an event which, with notice or lapse of time or both, would
constitute a default) under, or result in the termination or in a right of
termination or cancellation of, or accelerate the performance required by, or
result in the creation of any lien, security interest, charge or encumbrance
upon any of the properties of AIP or its Subsidiaries under, or result in being
declared void, voidable or without further binding effect, any of the terms,
conditions or provisions of any note, bond, mortgage, indenture, deed of trust
or any license, franchise, permit, lease, contract, agreement or other
instrument, commitment or obligation to which AIP or any of its Subsidiaries is
a party, or by which AIP or any of its Subsidiaries or any of their properties
is bound or affected, except for any of the foregoing matters which,
individually or in the aggregate, would not have an AIP Material Adverse
Effect; or (iii) other than the Regulatory Filings require any consent,
approval or authorization of, or declaration, filing or registration with, any
domestic governmental or regulatory authority, except where the failure to
obtain such consent, approval or authorization of, or declaration, filing or
registration with, any governmental or regulatory authority would not have an
AIP Material Adverse Effect.

       6.7.   SEC Documents.   (a)  AIP has made available or will make
available to RELP prior to September 30, 1997, the registration statements of
AIP filed with the SEC in connection with public offerings of AIP securities
since January 1, 1994 and all exhibits, amendments and supplements thereto (the
"AIP Registration Statements"), and each registration statement, report, proxy
statement or information statement and all exhibits thereto prepared by it or
relating to its properties since the effective date of the latest AIP
Registration Statement, each in the form (including exhibits and any amendments
thereto) filed with the SEC (collectively, the "AIP Reports"). The AIP Reports,
which were or will be filed with the SEC in a timely manner, constitute all
forms, reports and documents required to be filed by AIP under the Securities
Laws.





                                       12
<PAGE>   13
       (b)    To AIP's actual knowledge, as of their respective dates, the AIP
Reports (i) complied as to form in all material respects with the applicable
requirements of the Securities Laws, and (ii) did not contain any untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements made therein, in the light
of the circumstances under which they were made, not misleading. To AIP's
actual acknowledge, each of the consolidated balance sheets of AIP included in
or incorporated by reference into the AIP Reports (including the related notes
and schedules) fairly presents the consolidated financial position of AIP and
the AIP Subsidiaries as of its date and each of the consolidated statements of
income, retained earnings and cash flows of AIP included in or incorporated by
reference into the AIP Reports (including any related notes and schedules)
fairly presents the results of operations, retained earnings or cash flows, as
the case may be, of AIP and the AIP Subsidiaries for the periods set forth
therein (subject, in the case of unaudited statements, to normal year-end audit
adjustments which would not be material in amount or effect), in each case in
accordance with generally accepted accounting principles consistently applied
during the periods involved, except as may be noted therein and except, in the
case of the unaudited statements, as permitted by the Securities Laws.

       (c)    Except as and to the extent set forth on the consolidated balance
sheet of AIP and its Subsidiaries at March 31, 1997, including all notes
thereto, or as set forth in the AIP Reports, neither AIP nor any of the AIP
Subsidiaries has any material liabilities or obligations of any nature (whether
accrued, absolute, contingent or otherwise) that would be required to be
reflected on, or reserved against in, a balance sheet of AIP or in the notes
thereto, prepared in accordance with generally accepted accounting principles
consistently applied, except liabilities arising in the ordinary course of
business since such date which would not have an AIP Material Adverse Effect.

       6.8.    Litigation.   To AIP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which AIP or any AIP Subsidiary is a party or by
which any of its properties or assets are bound or, to which any of its
directors, officers, or affiliates is a party or by which any of their
properties or assets are bound, and (ii) except as will be set forth in the AIP
Disclosure Letter, no actions, suits or proceedings pending against AIP or any
AIP Subsidiary or, to the knowledge of AIP, against any of its Trust Managers,
officers, or affiliates or, to the knowledge of AIP, threatened against AIP or
any AIP Subsidiary or against any of its Trust Managers, officers, or
affiliates, at law or in equity, or before or by any federal or state
commission, board, bureau, agency or instrumentality, that in the case of
clauses (i) or (ii) above are reasonably likely, individually or in the
aggregate, to have an AIP Material Adverse Effect.

       6.9.    Absence of Certain Changes.  Except as disclosed in the AIP
Reports filed with the SEC prior to the date hereof, (i) AIP and its
Subsidiaries have conducted their business only in the ordinary course of such
business (which, for purposes of this section only, shall include all
acquisitions of real estate properties and financing arrangements made in
connection therewith); (ii) there has not been any AIP Material Adverse Effect;
(iii) there has not been any declaration, setting aside or payment of any
dividend or other distribution with respect to the AIP Common Shares; and (iv)
there has not been any material change in AIP's accounting principles,
practices or methods.





                                       13
<PAGE>   14
       6.10.  Taxes.  (a)  Except as may be set forth in the AIP Disclosure
Letter, AIP and each of its Subsidiaries (i) has timely filed all federal,
state and foreign tax returns including, without limitation, information
returns and reports required to be filed by any of them for tax periods ended
prior to the date of this Agreement or requests for extensions have been timely
filed and any such request has been granted and has not expired and all such
returns are absolute and complete in all material respects, (ii) has paid or
accrued all taxes shown to be due and payable on such returns or which have
become due and payable pursuant to any assessment, deficiency notice, 30-day
letter or other notice received by it and (iii) has properly accrued all taxes
for such periods subsequent to the periods covered by such returns. Neither AIP
nor any of its Subsidiaries has received notice that the federal, state and
local income and franchise tax returns of AIP or any such Subsidiary has been
or will be examined by any taxing authority. Neither AIP nor any of its
Subsidiaries has executed or filed with the IRS or any other taxing authority
any agreement now in effect extending the period for assessment or collection
of any income or other taxes.

       (b)    Except as will be disclosed in the AIP Disclosure Letter, neither
AIP nor any of its Subsidiaries is a party to any pending action or proceeding
by any governmental authority for assessment or collection of taxes, and no
claim for assessment or collection of taxes has been asserted against it. True,
correct and complete copies of all federal, state and local income or franchise
tax returns filed by AIP and each of its Subsidiaries and all communications
relating thereto have been delivered to RELP or made available to
representatives of RELP or will be so delivered or made available prior to
September 30, 1997. AIP (i) has qualified to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable years ended December 31,
1985 through 1996, inclusive (ii) has operated, and intends to continue to
operate, in such a manner as to qualify to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable year ended on the
effective date of the Merger, and (iii) has not taken or omitted to take any
action which could result in, and each of the executive officers of AIP, each
acting in his respective capacity as such, has no actual knowledge of, a
challenge to its status as a REIT. AIP represents that each of its Subsidiaries
is a Qualified REIT Subsidiary as defined in Section 856 (i) of the Code.
Neither AIP nor any of its Subsidiaries holds any asset (i) the disposition of
which could be subject to rules similar to Section 1374 of the Code as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 6.10, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

       6.11.  Books and Records.  (a)  The books of account and other financial
records of AIP and its Subsidiaries are in all material respects true, complete
and correct, have been maintained in accordance with good business practices,
and are accurately reflected in all material respects in the financial
statements included in the AIP Reports.

       (b)    The minute books and other records of AIP and its Subsidiaries
contain in all material respects accurate records of all meetings and
accurately reflect in all material respects all other corporate action of the
shareholders and Trust Managers and any committees of the Board of Trust
Managers of AIP and its Subsidiaries.





                                       14
<PAGE>   15
       6.12.  Properties.  (a)  AIP and its Subsidiaries own fee simple title
to each of the real properties reflected on the most recent balance sheet of
AIP included in the AIP Reports or as may be identified in the AIP Disclosure
Letter (the "AIP Properties"), which are all of the real estate properties
owned by them, free and clear of Encumbrances. To AIP's actual knowledge, the
AIP Properties are not subject to any rights of way, written agreements, laws,
ordinances and regulations affecting building use or occupancy, or reservations
of an interest in title (collectively, "Property Restrictions"), except for (i)
Encumbrances and Property Restrictions that will be set forth in the AIP
Disclosure Letter, (ii) Property Restrictions imposed or promulgated by law or
any governmental body or authority with respect to real property, including
zoning regulations, provided they do not materially adversely affect the
current use of the property, (iii) Encumbrances and Property Restrictions
disclosed on existing title reports or surveys (in either case copies of which
title reports and surveys have been or will be delivered or made available to
RELP prior to September 30, 1997), and (iv) mechanics', carriers', workmen's,
repairmen's liens and other Encumbrances, Property Restrictions and other
limitations of any kind, if any, which have heretofore been bonded (and that
will be listed in the AIP Disclosure Letter) or which individually or in the
aggregate, do not exceed $100,000, do not materially detract from the value of
or materially interfere with the present use of any of the AIP Properties
subject thereto or affected thereby, and do not otherwise materially impair
business operations conducted by AIP and its Subsidiaries and which have arisen
or been incurred only in its construction activities or in the ordinary course
of business.

       (b)    Valid policies of title insurance have been issued insuring AIP's
or any of its Subsidiaries' fee simple title to the AIP Properties, subject
only to the matters disclosed above and as may be set forth in the AIP
Disclosure Letter, and such policies are, at the date hereof, in full force and
effect and no material claim has been made against any such policy. To AIP's
actual knowledge, except as will be set forth in the AIP Disclosure Letter, (i)
there is no certificate, permit or license from any governmental authority
having jurisdiction over any of the AIP Properties or any agreement, easement
or other right which is necessary to permit the lawful use and operation of the
buildings and improvements on any of the AIP Properties or which is necessary
to permit the lawful use and operation of all driveways, roads and other means
of egress and ingress to and from any of the AIP Properties that has not been
obtained and is not in full force and effect, or of any pending threat of
modification or cancellation of any of same; (ii) neither AIP nor its
Subsidiaries has received written notice of any material violation of any
federal, state or municipal law, ordinance, order, regulation or requirement
affecting any portion of any of the AIP Properties issued by any governmental
authority; (iii) there are no structural defects relating to the AIP Properties
and no AIP Properties whose building systems are not in working order in any
material respect; and (iv) there is (A) no physical damage to any AIP Property
in excess of $100,000 for which there is no insurance in effect covering the
cost of the restoration, (B) no current renovation to any AIP Property the cost
of which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any AIP Property the cost of which exceeds $100,000.

       (c)    Except as will be set forth in the AIP Disclosure Letter, AIP or
its Subsidiaries have received no notice to the effect that and there are no
(A) condemnation or rezoning proceedings that are pending or threatened with
respect to any of the AIP Properties or (B) any zoning, building or similar
laws, codes, ordinances, orders or regulations that are or will be violated by
the continued maintenance, operation or use of any buildings or other
improvements on any of the AIP Properties or by the continued maintenance,
operation or use of the parking areas in any material respect. All





                                       15
<PAGE>   16
work to be performed, payments to be made and actions to be taken by AIP or its
Subsidiaries prior to the date hereof pursuant to any agreement entered into
with a governmental body or authority in connection with a site approval,
zoning reclassification or other similar action relating to the AIP Properties
(e.g., Local Improvement District, Road Improvement District, Environmental
Mitigation) has been performed, paid or taken, as the case may be, and AIP is
not aware of any planned or proposed work, payments or actions that may be
required after the date hereof pursuant to such agreements, except as will be
set forth in the AIP Disclosure Letter.

       6.13.  Environmental Matters.  To the actual knowledge of AIP, none of
AIP, any of its Subsidiaries or, any other person has caused or permitted (i)
the unlawful presence of any Hazardous Materials on any of the AIP Properties,
or (ii) any unlawful spills, releases, discharges or disposal of Hazardous
Materials to have occurred or be presently occurring on or from the AIP
Properties as a result of any construction on or operation and use of such
properties, which presence or occurrence would, individually or in the
aggregate, have an AIP Material Adverse Effect; and in connection with the
construction on or operation and use of the AIP Properties, AIP and its
Subsidiaries have not failed to comply, in any material respect, with any
applicable local, state and federal environmental laws, regulations, ordinances
and administrative and judicial orders relating to the generation, recycling,
reuse, sale, storage, handling, transport and disposal of any Hazardous
Materials.

       6.14.  Labor Matters.   Neither AIP nor any of its Subsidiaries is a
party to, or bound by, any collective bargaining agreement, contract or other
agreement or understanding with a labor union or labor union organization.
There is no unfair labor practice or labor arbitration proceeding pending or,
to the knowledge of the executive officers of AIP, threatened against AIP or
its Subsidiaries relating to their business, except for any such proceeding
which would not have an AIP Material Adverse Effect. To the knowledge of AIP,
there are no organizational efforts with respect to the formation of a
collective bargaining unit presently being made or threatened involving
employees of AIP or any of its Subsidiaries.

       6.15.  No Brokers.  Except for the fee payable to Prudential Securities
Incorporated ("Prudential") as described in Section 6.16 below, AIP has not
entered into any contract, arrangement or understanding  with any person or
firm which may result in the obligation of AIP or RELP to pay any finder's
fees, brokerage or agent's commissions or other like payments in connection
with the negotiations leading to this Agreement or the consummation of the
transactions contemplated hereby. AIP is not aware of any claim for payment of
any finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby.

       6.16.  Opinion of Financial Advisor.  AIP has retained Prudential to
review the transaction contemplated by this Agreement and to issue an opinion
as to the fairness to AIP, from a financial point of view, of the consideration
to be paid by AIP pursuant to the Merger.

       6.17.  RELP Share Ownership.  Except as may be set forth in the AIP
Disclosure Letter, neither AIP nor any of its Subsidiaries owns any RELP
Interests or other securities convertible into RELP interests.





                                       16
<PAGE>   17
       6.18.  AIP Common Shares.  The issuance and delivery by AIP of AIP
Common Shares in connection with the Merger and this Agreement have been duly
and validly authorized by all necessary action on the part of AIP except for
the approval of its shareholders contemplated by this Agreement. The AIP Common
Shares to be issued in connection with the Merger and this Agreement, when
issued in accordance with the terms of this Agreement, will be validly issued,
fully paid and nonassessable, except that shareholders may be subject to
further assessment with respect to certain claims for tort, contract, taxes,
statutory liability and otherwise in some jurisdictions to the extent such
claims are not satisfied by AIP.

       6.19.  Convertible Securities.  AIP has no outstanding options, warrants
or other securities exercisable for, or convertible into, shares of AIP Common
Shares, the terms of which would require any anti-dilution adjustments by
reason of the consummation of the transactions contemplated hereby, except the
preemptive rights held by certain clients of Morgan Stanley Asset Management,
Inc. and held by MS Real Estate Special Situations, Inc. and the convertible
debt securities held by Realco.

       6.20.  Related Party Transactions.  Set forth in the AIP Disclosure
Letter will be a list of all arrangements, agreements and contracts entered
into by AIP or any of its Subsidiaries with (i) any person who is an officer,
Trust Manager or affiliate of AIP or any of its Subsidiaries, any relative of
any of the foregoing or any entity of which any of the foregoing is an
affiliate or (ii) any person who acquired AIP Common Shares in a private
placement. The copies of such documents, all of which have been or will be
delivered or made available to RELP prior to September 30, 1997, are or will be
true, complete and correct when delivered or made available.

       6.21.  Contracts and Commitments.  The AIP Disclosure Letter will set
forth (i) all unsecured notes or other obligations of AIP and AIP Subsidiaries
which individually may result in total payments in excess of $100,000, (ii)
notes, debentures, bonds and other evidence of indebtedness which are secured
or collateralized by mortgages, deeds of trust or other security interests in
the AIP Properties or personal property of AIP and its Subsidiaries, and (iii)
each commitment entered into by AIP or any of its Subsidiaries which
individually may result in total payments or liability in excess of $100,000.
Copies of the foregoing have been or will be delivered or made available to
RELP prior to September 30, 1997, will be listed on the AIP Disclosure Letter
and are or will be materially true and correct when delivered or made
available. None of AIP or any of its Subsidiaries has received any notice of a
default that has not been cured under any of the documents described in clause
(i) or (ii) above or is in default respecting any payment obligations
thereunder beyond any applicable grace periods. All options of AIP or any of
its Subsidiaries to purchase real property will be set forth on the AIP
Disclosure Letter and such options and AIP's or its Subsidiaries' rights
thereunder are in full force and effect. All joint venture agreements to which
AIP or any of its Subsidiaries is a party will be set forth on the AIP
Disclosure Letter and AIP or its Subsidiaries are not in default with respect
to any obligations, which individually or in the aggregate are material,
thereunder.

       6.22.  Development Rights.  Set forth in the AIP Disclosure Letter will
be a list of all material agreements entered into by AIP or any of its
Subsidiaries relating to the development, rehabilitation, capital improvement
or construction of office buildings, industrial facilities or other real estate
properties which development or construction has not been substantially
completed as of





                                       17
<PAGE>   18
the date of this Agreement. Such agreements, true, complete and correct copies
of all of which have been or will be delivered or made available to RELP prior
to September 30, 1997, will be listed in the AIP Disclosure Letter.

       6.23. Certain Payments Resulting From Transactions.  The execution of,
and performance of the transactions contemplated by, this Agreement will not
(either alone or upon the occurrence of any additional or subsequent events)
(i) constitute an event under any AIP Benefit Plan, policy, practice, agreement
or other arrangement or any trust or loan (the "Employee Arrangements") that
will or may result in any payment (whether of severance pay or otherwise),
acceleration, forgiveness of indebtedness, vesting, distribution, increase in
benefits or obligation to fund benefits with respect to any employee, director
or consultant of AIP or any of its Subsidiaries unless such rights have been
waived by any such person, or (ii) result in the triggering or imposition of
any restrictions or limitations on the right of AIP or RELP to amend or
terminate any Employee Arrangement and receive the full amount of any excess
assets remaining or resulting from such amendment or termination, subject to
applicable taxes. No payment or benefit which will be required to be made
pursuant to the terms of any agreement, commitment or AIP Benefit Plan, as a
result of the transactions contemplated by this Agreement, to any officer,
director or employee of AIP or any of its Subsidiaries, will be characterized
as an "excess parachute payment" within the meaning of Section 280G(b)(1) of
the Code.

                            ARTICLE VII.  COVENANTS

       7.1.   Acquisition Proposals.   Prior to the Effective Time, RELP and
AIP each agree (i) that neither of them nor any of their Subsidiaries shall,
and each of them shall direct and use its best efforts to cause its respective
officers, General Partner, limited partners, Trust Managers, employees, agents,
affiliates and representatives (including, without limitation, any investment
banker, attorney or accountant retained by it or any of its Subsidiaries), as
applicable, not to, initiate, solicit or encourage, directly or indirectly, any
inquiries or the making or implementation of any proposal or offer (including,
without limitation, any proposal or offer to its shareholders) with respect to
a merger, acquisition, tender offer, exchange offer, consolidation or similar
transaction involving, or any purchase of all or any significant portion of the
assets or any equity securities (or any debt securities convertible into equity
securities) of, such party or any of its Subsidiaries, other than the
transactions contemplated by this Agreement (any such proposal or offer being
hereinafter referred to as an "Acquisition Proposal") or engage in any
negotiations concerning, or provide any confidential information or data to, or
have any discussions with, any person relating to an Acquisition Proposal, or
otherwise facilitate any effort or attempt to make or implement an Acquisition
Proposal; (ii) that it will immediately cease and cause to be terminated any
existing activities, discussions or negotiations with any parties conducted
heretofore with respect to any of the foregoing and each will take the
necessary steps to inform the individuals or entities referred to above of the
obligations undertaken in this Section 7.1; and (iii) that it will notify the
other party immediately if any such inquiries or proposals are received by, any
such information is requested from, or any such negotiations or discussions are
sought to be initiated or continued with, it; provided, however, that nothing
contained in this Section 7.1 shall prohibit the Board of Directors of the
General Partner of RELP (the "Board of Directors") or the Board of Trust
Managers from (x) furnishing information to or entering into discussions or
negotiations with, any person or entity that makes an unsolicited bona fide
Acquisition Proposal, if, and only to the extent that, (A) the Board





                                       18
<PAGE>   19
of Directors or Board of Trust Managers, as applicable, determines in good
faith that such action is required for it to comply with its fiduciary duties
to limited partners or shareholders, as applicable,  imposed by law as advised
by counsel, (B) prior to furnishing such information to, or entering into
discussions or negotiations with, such person or entity, such party provides
written notice to the other party to this Agreement to the effect that it is
furnishing information to, or entering into discussions with, such person or
entity, and (C) subject to any confidentiality agreement with such person or
entity (which such party determined in good faith was required to be executed
in order for the Board of Directors or Board of Trust Managers, as applicable,
to comply with its fiduciary duties to limited partners or shareholders, as
applicable,  imposed by law as advised by counsel), such party keeps the other
party to this Agreement informed of the status (but not the terms) of any such
discussions or negotiations; and (y) to the extent applicable, complying with
Rule 14e-2 promulgated under the Exchange Act with regard to an Acquisition
Proposal.

       Nothing in this Section 7.1 shall (i) permit any party to terminate this
Agreement (except as specifically provided in Article IX hereof), (ii) permit
any party to enter into any agreement with respect to an Acquisition Proposal
during the term of this Agreement (it being agreed that during the term of this
Agreement, no party shall enter into any agreement with any person that
provides for, or in any way facilitates, an Acquisition Proposal (other than a
confidentiality agreement in customary form)), or (iii) affect any other
obligation of any party under this Agreement.

       7.2.   Conduct of Businesses.

       (i)    Prior to the Effective Time, except as may be set forth in the
RELP Disclosure Letter or the AIP Disclosure Letter or as contemplated by this
Agreement, unless the other party has consented in writing thereto, AIP and
RELP:

       (a)    Shall use their reasonable efforts, and shall cause each of their
              respective Subsidiaries to use their reasonable efforts, to
              preserve intact their business organizations and goodwill and
              keep available the services of their respective officers and
              employees;

       (b)    Shall confer on a regular basis with one or more representatives
              of the other to report operational matters of materiality and,
              subject to Section 7.1, any proposals to engage in material
              transactions;

       (c)    Shall promptly notify the other of any material emergency or
              other material change in the condition (financial or otherwise)
              of the  business, properties, assets or  liabilities, or any
              material governmental complaints, investigations or hearings (or
              communications indicating that the same may be contemplated), or
              the breach in any material respect of any representation,
              warranty, covenant or agreement contained herein;

       (d)    Shall not pay quarterly dividends or make distributions payable
              with respect to the AIP Common Shares and RELP Partnership
              Interests, respectively; and

       (e)    Shall promptly deliver to the other true and correct copies of
              any report, statement or schedule filed with the SEC subsequent
              to the date of this Agreement.





                                       19
<PAGE>   20
       (ii)   Prior to the Effective Time, except as may be set forth in the
RELP Disclosure Letter, unless AIP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, RELP:

       (a)    Shall conduct its operations according to its usual, regular and
              ordinary course in substantially the same manner as heretofore
              conducted;

       (b)    Shall not amend the RELP Organizational Documents;

       (c)    Shall not (i) except pursuant to the exercise of options,
              warrants, conversion rights and other contractual rights existing
              on the date hereof and disclosed pursuant to this Agreement,
              issue any RELP Interests, make any distribution, effect any
              recapitalization or other similar transaction, (ii) grant, confer
              or award any option, warrant, conversion right or other right not
              existing on the date hereof to acquire any RELP Interest, (iii)
              increase any compensation or enter into or amend any employment
              agreement with any of its present or future officers or directors
              of the General Partner, or (iv) adopt any new employee benefit
              plan or amend any existing employee benefit plan in any material
              respect, except for changes which are less favorable to
              participants in such plans;

       (d)    Shall not declare, set aside or make any distribution or payment
              with respect to any RELP Interest or directly or indirectly
              redeem, purchase or otherwise acquire any RELP Interest, or make
              any commitment for any such action;

       (e)    Shall not sell or otherwise dispose of (i) any RELP Properties,
              or (ii) except in the ordinary course of business, any of its
              other assets which are material, individually or in the
              aggregate;

       (f)    Shall not make any loans, advances or capital contributions to,
              or investments in, any other person;

       (g)    Shall not pay, discharge or satisfy any claims, liabilities or
              obligations (absolute, accrued, asserted or unasserted,
              contingent or otherwise), other than the payment, discharge or
              satisfaction in the ordinary course of business consistent with
              past practice or in accordance with their terms, of liabilities
              reflected or reserved against in, or contemplated by, the most
              recent consolidated financial statements (or the notes thereto)
              of RELP included in the RELP Reports or incurred in the ordinary
              course of business consistent with past practice;

       (h)    Shall not enter into any commitment which individually may result
              in total payments or liability by or to it in excess of $250,000
              in the case of any one commitment or in excess of $500,000 for
              all commitments;





                                       20
<PAGE>   21
       (i)    Shall not, and shall not permit any of its Subsidiaries to, enter
              into any commitment with any officer, director or affiliate of
              RELP or  its General Partner except to the extent the same occur
              in the ordinary course of business consistent with past practice
              and would not have a RELP Material Adverse Effect; and

       (j)    Shall not enter into or terminate any lease representing annual
              revenues of $100,000 or more.

       (iii)  Prior to the Effective Time, except as may be set forth in the
AIP Disclosure Letter, unless RELP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, AIP:

       (a)    Shall, and shall cause each of its Subsidiaries to, conduct its
              operations according to their usual, regular and ordinary course
              in substantially the same manner as heretofore conducted;

       (b)    Shall not amend its Declaration of Trust or Bylaws except as
              contemplated by this Agreement;

       (c)    Shall not (i) except pursuant to the exercise of options,
              warrants, conversion rights and other contractual rights
              (including AIP's existing dividend reinvestment plan) existing on
              the date hereof and disclosed pursuant to this Agreement, issue
              any shares of its capital stock, effect any share split, reverse
              share split, share dividend, recapitalization or other similar
              transaction, (ii) grant, confer or award any option, warrant,
              conversion right or other right not existing on the date hereof
              to acquire any shares of its capital shares (except pursuant to
              any employee incentive plan approved by shareholders), (iii)
              amend any employment agreement with any of its present or future
              officers or Trust Managers, or (iv) adopt any new employee
              benefit plan (including any share option, share benefit or share
              purchase plan) except the employee incentive plan to be voted on
              at its shareholder meeting for the fiscal year ended December 31,
              1995;

       (d)    Shall not declare, set aside or pay any dividend or make any
              other distribution or payment with respect to any Common Shares
              or directly or indirectly redeem, purchase or otherwise acquire
              any Common Shares or capital stock of any of its Subsidiaries, or
              make any commitment for any such action;

       (e)    Except as will be set forth in the AIP Disclosure Letter, shall
              not, and shall not permit any of its Subsidiaries to, sell or
              otherwise dispose of (i) any AIP Properties or any of its capital
              stock of or other interests in Subsidiaries or (ii) except in the
              ordinary course of business, any of its other assets which are
              material, individually or in the aggregate;

       (f)    Shall not, and shall not permit any of its Subsidiaries to, make
              any loans, advances or capital contributions to, or investments
              in, any other person other than in connection with the sale of
              properties;





                                       21
<PAGE>   22
       (g)    Shall not, and shall not permit any of its Subsidiaries to, pay,
              discharge or satisfy any claims, liabilities or obligations
              (absolute, accrued, asserted or unasserted, contingent or
              otherwise), other than the payment, discharge or satisfaction in
              the ordinary course of business consistent with past practice or
              in accordance with their terms, of liabilities reflected or
              reserved against in, or contemplated by, the most recent
              consolidated financial statements (or the notes thereto) of AIP
              included in the AIP Reports or incurred in the ordinary course of
              business consistent with past practice;

       (h)    Shall not, and shall not permit any of its Subsidiaries to, enter
              into any commitment which individually may result in total
              payments or liability by or to it in excess of $500,000 in the
              case of any one commitment or in excess of $500,000 for all
              commitments; and

       (i)    Shall not, and shall not permit any of its Subsidiaries to, enter
              into any commitment with any officer, Trust Manager or affiliate
              of AIP or any of its Subsidiaries, except as herein or in the AIP
              Disclosure Letter provided and except in the ordinary course of
              business.

For purposes of this Section 7.2, any consent shall be deemed to be
unreasonably delayed if notice of consent or withholding of consent is not
received within three days of request.  Further, if no response is received by
the end of business on such third day, the party receiving the request shall be
deemed to have consented to such action.

       7.3    Meetings of Shareholders and Partners.  Each of AIP and RELP will
take all action necessary in accordance with applicable law and its
organizational documents  to convene a meeting of its shareholders or partners,
as applicable,  as promptly as practicable to consider and vote upon or
otherwise to obtain the consent of its shareholders or partners, as applicable,
to (i) in the case of AIP, approve this Agreement and the transactions
contemplated hereby, and (ii) in the case of RELP, approve this Agreement and
the transactions contemplated hereby. The Board of Trust Managers and the
General Partner shall each recommend such approval and AIP and RELP shall each
take all lawful action to solicit such approval, including, without limitation,
timely mailing the Proxy Statement/Prospectus (as defined in Section 7.7);
provided, however, that such recommendation or solicitation is subject to any
action taken by, or upon authority of, the Board of Trust Managers or the
General Partner, as the case may be, in the exercise of its good faith judgment
as to its fiduciary duties to its shareholders or partners, as applicable,
imposed by law as advised by counsel. AIP and RELP shall coordinate and
cooperate with respect to the timing of such meetings and shall use their best
efforts to hold such meetings on the same day.

       7.4.    Filings; Other Action.  Subject to the terms and conditions
herein provided, RELP and AIP shall: (a) use all reasonable efforts to
cooperate with one another in (i) determining which filings are required to be
made prior to the Effective Time with, and which consents, approvals, permits
or authorizations are required to be obtained prior to the Effective Time from
governmental or regulatory authorities of the United States and the several
states in connection with the execution and delivery of this Agreement and the
consummation of the transactions contemplated hereby and (ii) timely making all
such filings and timely seeking all such consents, approvals, permits or
authorizations; (b) use all reasonable efforts to obtain in writing any
consents required from third





                                       22
<PAGE>   23
parties in form reasonably satisfactory to RELP and AIP necessary to effectuate
the Merger; and (c) use all reasonable efforts to take, or cause to be taken,
all other action and do, or cause to be done, all other things necessary,
proper or appropriate to consummate and make effective the transactions
contemplated by this Agreement. If, at any time after the Effective Time, any
further action is necessary or desirable to carry out the purpose of this
Agreement, the proper officers and directors of AIP and the General Partner
shall take all such necessary action.

       7.5.   Inspection of Records.  From the date hereof to the Effective
Time, each of RELP and AIP shall allow all designated officers, attorneys,
accountants and other representatives of the other access at all reasonable
times to the records and  files, correspondence, audits and properties, as well
as to all information relating to commitments, contracts, titles and financial
position, or otherwise pertaining to the business and affairs of RELP and AIP
and their respective Subsidiaries.

       7.6.   Publicity.  RELP and AIP shall, subject to their respective legal
obligations (including requirements of stock exchanges and other similar
regulatory bodies), consult with each other, and use reasonable efforts to
agree upon the text of any press release before issuing any such press release
or otherwise making public statements with respect to the transactions
contemplated hereby and in making any filings with any federal or state
governmental or regulatory agency or with any national securities exchange with
respect thereto.

       7.7.   Registration Statement.  AIP and RELP shall cooperate and
promptly prepare and AIP shall file with the SEC as soon as practicable a
Registration Statement on Form S-4 (the "Form S-4") under the Securities Act,
with respect to the AIP Common Shares issuable in the Merger, a portion of
which Registration Statement shall also serve as the joint proxy statement with
respect to the meetings of the shareholders and partners, respectively, of AIP
and RELP in connection with the Merger (the "Proxy Statement/Prospectus"). The
respective parties will cause the Proxy Statement/Prospectus and the Form S-4
to comply as to form in all material respects with the applicable provisions of
the Securities Act, the Exchange Act and the rules and regulations promulgated
thereunder. AIP shall use all reasonable efforts, and RELP will cooperate with
AIP to have the Form S-4 declared effective by the SEC as promptly as
practicable. AIP shall use its best efforts to obtain, prior to the effective
date of the Form S-4, all necessary state securities law or "Blue Sky" permits
or approvals required to carry out the transactions contemplated by this
Agreement and will pay all expenses incident thereto. AIP agrees that the Proxy
Statement/Prospectus and each amendment or supplement thereto, at the time of
mailing thereof and at the time of the respective meetings of shareholders and
partners, respectively, of AIP and RELP, or, in the case of the Form S-4 and
each amendment or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading; provided, however, that the foregoing shall not apply to the
extent that any such untrue statement of a material fact or omission to state a
material fact was made by AIP in reliance upon and in conformity with written
information concerning RELP furnished to AIP by RELP specifically for use in
the Proxy Statement/Prospectus. RELP agrees that the written information
provided by it specifically for inclusion in the Proxy Statement/Prospectus and
each amendment or supplement thereto, at the time of mailing thereof and at the
time of the respective meetings of shareholders and partners, respectively, of
AIP and RELP, or, in the case of written information provided by RELP
specifically for inclusion in the Form S-4





                                       23
<PAGE>   24
or any amendments or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading. AIP will advise RELP, promptly after it receives notice
thereof, of the time when the Form S-4 has become effective or any supplement
or amendment has been filed, the issuance of any stop order, the suspension of
the qualification of the AIP Common Shares issuable in connection with the
Merger for offering or sale in any jurisdiction, or any request by the SEC for
amendment of the Proxy Statement/Prospectus or the Form S-4 or comments thereon
and responses thereto or requests by the SEC for additional information.

       7.8.   Listing Application.  AIP shall promptly prepare and submit to
the NYSE a listing application covering the AIP Common Shares issuable in the
Merger, and shall use its reasonable efforts to obtain, prior to the Effective
Time, approval for the listing of such AIP Common Shares, subject to official
notice of issuance.

       7.9.   Further Action.  Each party hereto shall, subject to the
fulfillment at or before the Effective Time of each of the conditions of
performances set forth herein or the waiver thereof, perform such further acts
and execute such documents as may reasonably be required to effect the Merger.

       7.10.  Expenses.  Subject to Section 9.5, if the Merger is approved by
RELP's partners, all transaction costs of the proposed consolidation shall be
paid by AIP.  If three of the four limited partnerships party to the Proxy
Statement/Prospectus (the "Other RELPS") do not approve their proposed merger
into AIP, Realco shall reimburse AIP for AIP's expenses relating to the
proposed merger up to $250,000.  If RELP and the Other RELPS approve their
proposed merger into AIP, but the shareholders of AIP do not approve the
proposer merger, and if Realco voted its AIP Common Shares in favor of such
mergers, AIP will reimburse RELP and the Other RELPS for all expenses they
incurred in connection with the proposed merger.  Any expenses to be reimbursed
hereunder shall include, but not be limited to, costs of fairness opinions,
property appraisals, engineering and environmental reports, title policies,
accounting fees, legal fees, printing and solicitation expenses.  RELP will
bear the costs of preparing its initial fairness opinion, with later
reimbursement by AIP in the event the Merger is approved by RELP's partners.
If the limited partners of RELP fail to approve the proposed Merger, then
Realco will reimburse AIP for the RELP's expenses (to the extent paid by AIP)
as follows: the actual cost of such RELP's fairness opinion, legal fees up to
$80,000, and the actual cost or the Allocable Share  (if the actual cost is not
separately determined), of RELP's accounting fees, engineering and
environmental reports, printing and solicitation expenses.  Allocable Share,
for this purpose, shall be the ratio of such RELP's net book value of assets at
March 31, 1997 to the total net book value of all of the assets of RELP and the
Other RELPS at March 31, 1997.

       7.11.  Indemnification.  For a period of six years from and after the
Effective Time, AIP shall indemnify the partners, or agents of RELP who at any
time prior to the Effective Time were entitled to indemnification under the
Agreement of Limited Partnership of RELP existing on the date hereof to the
same extent as such partners or agents are entitled to indemnification under
such Agreement of Limited Partnership in respect of actions or omissions
occurring at or prior to the Effective Time (including, without limitation, the
transactions contemplated by this Agreement).





                                       24
<PAGE>   25
       7.12.  REIT Status.   From and after the date and until the Effective
Time, neither AIP nor RELP nor any of their respective Subsidiaries or other
affiliates shall (i) knowingly take any action, or knowingly fail to take any
action, that would jeopardize qualification of AIP as a REIT within the meaning
of Sections 856 through 859 of the Code; or (ii) enter into any contract,
agreement, commitment or arrangement with respect to the foregoing.

       7.13.  Survival of RELP Obligations; Assumption of RELP Liabilities by
AIP.  All of the obligations of RELP that are outstanding at the Closing shall
survive the Closing and shall not be merged therein. Upon the consummation of
the Merger, such obligations shall be assumed, automatically, by AIP; provided,
however, that such assumption shall not impose upon or expose AIP to any
liability for which RELP was not liable, and provided, further, that AIP shall
be entitled to the same defenses, offsets and counterclaims to which RELP would
have been entitled, but for the Merger.

       7.14.  Third Party Consents.  AIP and RELP each shall take all necessary
corporate and other action and will use its commercially reasonable efforts to
obtain the consents and applicable approvals from third parties that may be
required to enable it to carry out the transactions contemplated by this
Agreement.

       7.15.  Efforts to Fulfill Conditions.  AIP and RELP each shall use
commercially reasonable efforts to insure that all conditions precedent to its
obligations hereunder are fulfilled at or prior to the Closing.

       7.16.  Representations, Warranties and Conditions Prior to Closing.  AIP
and RELP each shall use its commercially reasonable efforts to cause its
representations and warranties contained in this Agreement to be true and
correct on and as of the Closing Date in all material respects. Prior to
Closing, AIP and RELP each shall promptly notify the other in writing (i) if
any representation or warranty contained in this Agreement is discovered to be
or becomes untrue or (ii) if AIP or RELP fails to perform or comply with any of
its covenants or agreements contained in this Agreement or it is reasonably
expected that it will be unable to perform or comply with any of its covenants
or agreements contained in this Agreement.

       7.17.  Cooperation of the Parties.  AIP and RELP each will cooperate
with the other in supplying such information as may be reasonably requested by
the other in connection with obtaining consents or approvals to the
transactions contemplated by this Agreement.

       7.18.  Lock-Ups.  The General Partner shall use its best efforts prior
to the Closing to have each of its directors and officers and Realco execute a
90-day lock-up agreement in a form (reasonably acceptable to RELP) supplied to
RELP by AIP. The executed agreements will be delivered to AIP at the Closing.
AIP shall use its best efforts prior to the Closing to have each of its Trust
Managers and officers execute a 90-day lock-up agreement, in a form (reasonably
acceptable to AIP) supplied to AIP by RELP. The agreements will be delivered to
RELP at the Closing.





                                       25
<PAGE>   26
                           ARTICLE VIII.  CONDITIONS

       8.1.   Conditions to Each Party's Obligations to Effect the Merger.  The
respective obligation of each party to effect the Merger shall be subject to
the fulfillment at or prior to the Closing Date of the following conditions:

       (a)    This Agreement and the transactions contemplated hereby shall
              have been approved in the manner required by the Declaration of
              Trust  and Bylaws and Agreement of Limited Partnership of AIP and
              RELP, respectively, and by applicable law or by applicable
              regulations of any stock exchange or other regulatory body by the
              holders of the AIP Common Shares and RELP Interests entitled to
              vote thereon.

       (b)    Neither of the parties hereto shall be subject to any order or
              injunction of a court of competent jurisdiction which prohibits
              the consummation of the transactions contemplated by this
              Agreement. In the event any such order or injunction shall have
              been issued, each party agrees to use its reasonable efforts to
              have any such injunction lifted.

       (c)    The Form S-4 shall have become effective and all necessary state
              securities law or "Blue Sky" permits or approvals required to
              carry out the transactions contemplated by this Agreement shall
              have been obtained and no stop order with respect to any of the
              foregoing shall be in effect.

       (d)    AIP shall have obtained the approval for the listing of the AIP
              Common Shares issuable in the Merger on the NYSE, subject to
              official notice of issuance.

       (e)    All consents, authorizations, orders and approvals of (or filings
              or registrations with) any governmental commission, board, other
              regulatory body or third parties required in connection with the
              execution, delivery and performance of this Agreement shall have
              been obtained or made, except for filings in connection with the
              Merger and any other documents required to be filed after the
              Effective Time and except where the failure to have obtained or
              made any such consent, authorization, order, approval, filing or
              registration would not have a material adverse effect on the
              business, results of operations or financial condition of AIP and
              RELP (and their respective Subsidiaries), taken as a whole,
              following the Effective Time.

       8.2    Conditions to Obligations of RELP to Effect the Merger.  The
obligation of RELP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by
RELP:

       (a)    AIP shall have performed its agreements contained in this
              Agreement required to be performed on or prior to the Closing
              Date and the representations and warranties of AIP contained in
              this Agreement shall be true and correct in all material respects
              as of the Closing Date as if made on the Closing Date, and RELP
              shall have received a certificate of the President or an
              Executive or Senior Vice President of AIP, dated the Closing
              Date, certifying to such effect.





                                       26
<PAGE>   27
       (b)    RELP shall have received the opinion of Liddell, Sapp or another
              recognized law firm selected by AIP and approved by RELP, dated
              the Closing Date, to the effect that AIP met the requirements for
              qualification and taxation as a REIT for its taxable year ending
              December 31, 1985, and has met the requirements for qualification
              and taxation as a REIT for its taxable years 1986 through 1996;
              AIP's diversity of equity ownership, operations through the
              Closing Date and proposed method of operation for future periods
              should allow it to qualify as a REIT for its taxable year ending
              December 31, 1997; and the discussion contained under the caption
              "Material Federal Income Tax Consequences" in the Proxy
              Statement/Prospectus accurately reflects existing law and fairly
              addresses the material Federal income tax issues described
              therein.  In rendering its opinion, said counsel shall be
              entitled to rely as to any factual matter upon certificates given
              by executive officers and other duly authorized representatives
              of RELP and AIP and shall be entitled to assume that the
              covenants set forth in Article VII shall be fully complied with.

       (c)    From the date of the Agreement through the Effective Time, there
              shall not have occurred any change in the financial condition,
              business or operations of AIP and its Subsidiaries, taken as a
              whole, that would have or would be reasonably likely to have an
              AIP Material Adverse Effect other than any such change that
              affects both RELP and AIP in a substantially similar manner.

       (d)    The opinion of Houlihan addressed to RELP that the Purchase Price
              is fair, from a financial point of view, to the partners of RELP
              shall not have been withdrawn or materially modified.

       (e)    RELP shall have received the opinion of Liddell, Sapp or another
              recognized law firm selected by AIP and approved by RELP, dated
              the Closing Date, as to such customary matters as RELP may
              reasonably request, such opinion to be reasonably satisfactory to
              RELP.

       8.3    Conditions to Obligation of AIP to Effect the Merger.  The
obligations of AIP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by AIP:


       (a)    RELP shall have performed its agreements contained in this
              Agreement required to be performed on or prior to the Closing
              Date and the representations and warranties of RELP contained in
              this Agreement shall be true and correct in all material respects
              as of the Closing Date as if made on the Closing Date and AIP
              shall have received a certificate of the Chief Executive Officer,
              President or an Executive Vice President of the General Partner
              dated the Closing Date, certifying to such effect.

       (b)    AIP shall have received the opinion of Liddell, Sapp or another
              recognized law firm selected by RELP and approved by AIP, dated
              the Closing Date, to the effect that the consummation of the
              Merger will not result in AIP's failure to continue to satisfy
              the requirements for qualification as a REIT for federal income
              tax purposes. In rendering its opinion, said counsel shall be
              entitled to rely as to any factual matter





                                       27
<PAGE>   28
              upon certificates given by executive officers and other duly
              authorized representatives of AIP and RELP and shall be entitled
              to assume that the covenants of Article VII shall be fully
              complied with.

       (c)    From the date of this Agreement through the Effective Time, there
              shall not have occurred any change in the financial condition,
              business or operations of RELP and its Subsidiaries, taken as a
              whole, that would have or would be reasonably likely to have an
              RELP Material Adverse Effect, other than any such change that
              affects both RELP and AIP in a substantially similar manner.

       (d)    Each person listed on Exhibit 8.3(d) attached hereto shall have
              delivered to AIP a written agreement to the effect that such
              person will not offer to sell, sell or otherwise dispose of any
              shares of AIP Common Stock issued in the Merger, except, in each
              case, pursuant to an effective registration statement or in
              compliance with Rule 145, as amended from time to time, or in a
              transaction which, in the opinion of legal counsel reasonably
              satisfactory to AIP, is exempt from the registration requirements
              of the Securities Act and that the certificates representing the
              AIP shares issued to him or her in the Merger may bear a legend
              to such effect.

       (e)    The opinion of Prudential addressed to the Board of Trust
              Managers of AIP that the consideration to be paid by AIP pursuant
              to the Merger is fair, from a financial point of view, to AIP
              shall not have been withdrawn or materially modified.

       (f)    AIP shall have received the opinion of Liddell, Sapp or another
              recognized law firm selected by RELP and approved by AIP, dated
              the Closing Date, as to such customary matters as AIP may
              reasonably request, such opinion to be reasonably satisfactory to
              AIP.

       (g)    The limited partners of at least two of the Other RELPS shall
              have approved the merger of such limited partnership with and
              into AIP.

                            ARTICLE IX.  TERMINATION

       9.1    Termination by Mutual Consent.  This Agreement may be terminated
and the Merger may be abandoned at any time prior to the Effective Time, before
or after the approval of this Agreement by the partners of RELP or the
shareholders of AIP or by the mutual written consent of AIP and RELP, with the
prior approval of their respective Board of Trust Managers and General Partner.


       9.2    Termination by Either AIP or RELP.  This Agreement may be
terminated and the Merger may be abandoned by action of the General Partner of
RELP or the Board of Trust Managers of AIP if (i) the Merger shall not have
been consummated by March 31, 1998, (ii) a meeting of RELP's partners shall
have been duly convened and held and the approval of RELP's partners required
by Section 8.1(a) shall not have been obtained at such meeting or at any
adjournment thereof, (iii) a meeting of AIP's shareholders shall have been duly
convened and held and the approval of AIP's shareholders required by Section
8.1(a) shall not have been obtained at such





                                       28
<PAGE>   29
meeting or at any adjournment thereof, (iv) as a result of due diligence
investigation by one of the parties hereto, it is determined in good faith by
such party that certain facts or circumstances not previously known by such
party constitute a Material Adverse Effect on the business, results of
operations or financial condition of the other party, (v) a United States
federal or state court of competent jurisdiction or United States federal or
state governmental, regulatory or administrative agency or commission shall
have issued an order, decree or ruling or taken any other action permanently
restraining, enjoining or otherwise prohibiting the transactions contemplated
by this Agreement and such order, decree, ruling or other action shall have
become final and non-appealable, provided that the party seeking to terminate
this Agreement pursuant to this clause (v) shall have used all reasonable
efforts to remove such order, decree, ruling or injunction, or (vi) any of the
conditions set forth in Article VIII shall not have been satisfied,  and
provided, in the case of a termination pursuant to clause (i) or (vi) above,
that the terminating party shall not have breached in any material respect its
obligations under this Agreement in any manner that shall have proximately
contributed to the occurrence of the failure referred to in said clause. AIP
and RELP each shall (i) deliver its Disclosure Letter to one another not later
than 5:00 P.M., Central Time, September 20, 1997, and (ii) shall complete its
due diligence investigations not later than 5:00 P.M., Central Time, on
September 30, 1997.  Until October 7, 1997 (the period from the date of this
Agreement through October 7, 1997 being hereinafter referred to as the "Due
Diligence Period"), either party may terminate this Agreement without liability
or penalty due to the discovery of a fact or circumstance that reasonably could
be expected to constitute a Material Adverse Effect on the business, results of
operations or financial condition of the other party.  Unless objected to by
the party receiving the Disclosure Letter in writing prior to the expiration of
the Due Diligence Period, the receiving party shall be deemed to have approved
the other party's Disclosure Letter.

       9.3     Termination by RELP.  This Agreement may be terminated and the
Merger may be abandoned at any time prior to the Effective Time, before or
after the adoption and approval by the partners of RELP referred to in Section
8.1(a), by action of the General Partner, if (i) in the exercise of its good
faith judgment as to its fiduciary duties to its partners imposed by law, as
advised by counsel, the General Partner determines that such termination is
required by reason of a RELP Acquisition Proposal being made, (ii) the Board of
Trust Managers withdraws, materially modifies or changes in a manner materially
adverse to RELP its recommendations to AIP's shareholders of this Agreement or
the Merger, other than as a result of the occurrence of an event that in the
good faith judgment of the Board of Trust Managers has or is reasonably likely
to have a RELP Material Adverse Effect, (iii) the Board of Trust Managers
postpones the date scheduled for the meeting of shareholders of AIP to approve
this Agreement and the transactions contemplated hereby beyond March 31, 1998
or fails to set a date for such meeting by such date, except with the written
consent of RELP, (iv) there has been a breach by AIP of any representation or
warranty contained in this Agreement which would have or would be reasonably
likely to have an AIP Material Adverse Effect, which breach is not curable by
March 31,1998, or (v) there has been material breach of any of the covenants or
agreements set forth in this Agreement on the part of AIP, which breach is not
curable or, if curable, is not cured within 30 days after written notice of
such breach is given by RELP to AIP, or (vi) the condition set forth in Section
8.3(g) is not satisfied..

       9.4    Termination by AIP.  This Agreement may be terminated and the
Merger may be abandoned at any time prior to the Effective Time, before or
after the approval by the shareholders of AIP referred to in Section 8.1(a), by
action of the Board of Trust Managers,  if (i) in the exercise





                                       29
<PAGE>   30
of its good faith judgment as to its fiduciary duties to its shareholders
imposed by law, as advised by counsel, the Board of Trust Managers determines
that such termination is required by reason of an AIP Acquisition Proposal
being made, (ii) the General Partner withdraws, materially modifies or changes
in a manner materially adverse to AIP its recommendation to RELP's partners of
this Agreement or the Merger, other than as a result of the occurrence of an
event that in the good faith judgment of the General Partner has or is
reasonably likely to have an AIP Material Adverse Effect, (iii) the General
Partner postpones the date scheduled for the meeting of partners of RELP to
approve this Agreement and the transactions contemplated hereby beyond March
31, 1998, or fails to set a date for such meeting by such date, except with the
written consent of AIP, (iv) there has been a breach by RELP of any
representation or warranty contained in this Agreement which would have or
would be reasonably likely to have a RELP Material Adverse Effect, which breach
is not curable by March 31, 1998, or (v) there has been a material breach of
any of the covenants or agreements set forth in this Agreement on the part of
RELP, which breach is not curable or, if curable, is not cured within 30 days
after written notice of such breach is given by AIP to RELP.

       9.5.   Effect of Termination and Abandonment.  (a)  If an election to
terminate this Agreement is made pursuant to (i) Section 9.2(i) (except as a
result of a default or breach hereunder by AIP) or Section 9.2(ii), and a RELP
Acquisition Proposal relating to RELP shall have been made and, within one year
from the date of such termination, RELP consummates a RELP Acquisition Proposal
or enters into an agreement to consummate a RELP Acquisition Proposal which is
subsequently consummated, or (ii) Section 9.3(i), RELP shall pay to AIP,
provided that AIP was not in material breach of its obligations hereunder at
the time of such termination, as liquidated damages and not as a penalty or
forfeiture, an amount equal to the lesser of (m) $352,200 (the "Liquidated
Damages Amount") and (n) the sum of (1) the maximum amount that can be paid to
AIP without causing AIP to fail to meet the requirements of Sections 856(c)(2)
and (3) of the Code determined as if the payment of such amount did not
constitute income described in Sections 856(c)(2)(A)-(H) and 856(c)(3)(A)-(I)
of the Code ("Qualifying Income"), as determined by AIP's certified public
accountants, plus (2) an amount equal to the Liquidated Damages Amount less the
amount payable under clause (1) above in the event AIP receives a letter from
AIP's counsel indicating that AIP has received a ruling from the IRS to the
effect that Liquidated Damages Amount payments constitute Qualifying Income. In
addition to the Liquidated Damages Amount, AIP shall be entitled to receive
from RELP (or its successor in interest) all documented out-of-pocket costs and
expenses, up to a maximum of $176,100 in connection with this Agreement and the
transactions contemplated hereby (the "AIP Expenses") incurred by AIP. The
payments to which AIP is entitled under this Section 9.5(a) shall be its sole
remedy with respect to the termination of the Agreement under the circumstances
contemplated in this Section 9.5(a).

       (b)    If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.3(c) not
being satisfied), RELP shall, provided that AIP was not in material breach of
its obligations hereunder at the time of such termination, pay AIP for the AIP
Expenses, up to a maximum of $176,100, although it shall not be required to pay
the Liquidated Damages Amount, which payment of the AIP Expenses shall be AIP's
sole remedy for termination of the Agreement in such circumstances.

       (c)    If an election to terminate this Agreement is made pursuant to
(i) Section 9.2(i) (except as a result of a default or breach hereunder by
RELP) or Section 9.2(iii), and an AIP





                                       30
<PAGE>   31
Acquisition Proposal relating to AIP shall have been made and, within one year
from the date of such termination, AIP consummates an AIP Acquisition Proposal
or enters into an agreement to consummate an AIP Acquisition Proposal which is
subsequently consummated, or (ii) Section 9.4(i), AIP shall pay to RELP,
provided that RELP was not in material breach of its obligations hereunder at
the time of such termination, as liquidated damages and not as a penalty or
forfeiture, an amount equal to the Liquidated Damages Amount. In addition to
the Liquidated Damages Amount, RELP shall be entitled to receive from AIP (or
its successor in interest) all documented out-of-pocket costs and expenses, up
to a maximum of $176,100, in connection with this Agreement and the
transactions contemplated hereby (the "RELP Expenses" and, together with the
AIP Expenses, the "Expenses")  incurred by RELP. The payments to which RELP is
entitled under this Section 9.5(c) shall be its sole remedy with respect to the
termination of the Agreement under the circumstances contemplated in this
Section 9.5(c)

       (d)    If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.2(c) not
being satisfied), AIP shall, provided that RELP was not in material breach of
its obligations hereunder at the time of such termination, pay RELP for the
RELP Expenses, up to a maximum of $176,100, although it shall not be required
to pay the Liquidated Damages Amount, which payment of the RELP Expenses shall
be RELP's sole remedy for termination of the Agreement in such circumstances.

       (e)    If this Agreement is terminated pursuant to Section 9.3(iv),
Section 9.3(v), Section 9.4(iv), or Section 9.4(v), the non-terminating party
shall, provided that the terminating party was not in material breach of its
obligations hereunder at the time of such termination, pay the terminating
party all Expenses, up to a maximum of $176,100, incurred by it and the non-
terminating party shall remain liable to the terminating party for its breach.

       (f)     If either party terminates this Agreement during the Due
Diligence Period described in Section 9.2 above other than for a due diligence
related reason, the non-terminating party shall be entitled to receive the
Liquidated Damages Amount and the Expenses as provided in this Article IX.

       (g)    RELP agrees to amend this Section 9.5 at the request of AIP in
order to (x) maximize the portion of the Liquidated Damages Amount that may be
distributed to AIP hereunder without causing AIP to fail to meet the
requirements of Sections 856(c)(2) and (3) of the Code or (y) improve AIP's
chances of securing a favorable ruling described in this Section 9.5, provided
that no such amendment may result in any additional cost or expense to such
other party.

       (h)    In the event of termination of this Agreement and the abandonment
of the Merger pursuant to this Article IX, all obligations of the parties
hereto shall terminate, except the obligations of the parties pursuant to this
Section 9.5 and Section 7.10 and except for the provisions of Section 10.3,
10.4, 10.5, 10.6, 10.7, 10.9, 10.10, 10.13, 10.14 and 10.16. In the event AIP
or RELP has received the Liquidated Damages Amount, such recipient shall not
assert or pursue in any manner, directly or indirectly, any claim or cause of
action against the other party hereto or any of its officers, Trust Managers,
or  General Partners, as applicable, based in whole or part upon its or their
receipt, consideration, recommendation or approval of an Acquisition Proposal
or the exercise by AIP of its right to termination under Section 9.4(i) or the
exercise by RELP of its right to termination under Section 9.3(i).
Notwithstanding the foregoing, in the event AIP or RELP is required to file
suit to





                                       31
<PAGE>   32
seek all or a portion of such Liquidated Damages Amount, and it ultimately
succeeds, it shall be entitled to all expenses, including attorney's fees and
expenses, which it has incurred in enforcing its right hereunder.

       (i)    If either party willfully fails to perform its duties and
obligations under this Agreement, the non-breaching party is additionally
entitled to all remedies available to it at law or in equity and to recover its
expenses from the breaching party.

       9.6    Extension; Waiver.  At any time prior to the Effective Time, any
party hereto, by action taken by its Board of Trust Managers or General
Partner, as applicable, may, to the extent legally allowed, (i) extend the time
for the performance of any of the obligations or other acts of the other
parties hereto, (ii) waive any inaccuracies in the representations and
warranties made to such party contained herein or in any document delivered
pursuant hereto and (iii) waive compliance with any of the agreements or
conditions for the benefit of such party contained herein. Any agreement on the
part of a party hereto to any such extension or waiver shall be valid only if
set forth in an instrument in writing signed on behalf of such party.

                         ARTICLE X.  GENERAL PROVISIONS

       10.1.  Nonsurvival of Representations, Warranties and Agreements.  All
representations, warranties and agreements in this Agreement or in any
instrument delivered pursuant to this Agreement shall not survive the Merger;
provided, however, that the agreements contained in Article IV, the last
sentence of Section 7.4 and Sections 7.10, 7.11, 7.12, 7.13, 7.14, 7.15 and
7.16 and this Article X shall survive the Merger.

       10.2.   Notices.  Any notice required to be given hereunder shall be in
writing and shall be sent by facsimile transmission (confirmed by any of the
methods that follow), courier service (with proof of service), hand delivery or
certified or registered mail (return receipt requested and first-class postage
prepaid) and addressed as follows:

       If to AIP:
       American Industrial Properties REIT
       6220 N. Beltline Road, Suite 205
       Irving, Texas 75063
       Attention: Charles W. Wolcott, President
       Telecopy: (972) 550-6037

       If to RELP:
       USAA Real Estate Company
       8000 I-H 10 West, Suite 600
       San Antonio, Texas 78230
       Attention: Patrick Duncan, Senior Vice-President
       Telecopy: (210) 498-6214

or to such other address as any party shall specify by written notice so given,
and such notice shall be deemed to have been delivered as of the date so
delivered.





                                       32
<PAGE>   33
       10.3.  Assignment; Binding Effect; Benefit.  Neither this Agreement nor
any of the rights, interests or obligations hereunder shall be assigned by any
of the parties hereto (whether by operation of law or otherwise) without the
prior written consent of the other parties. Subject to the preceding sentence,
this Agreement shall be binding upon and shall inure to the benefit of the
parties hereto and their respective successors and assigns. Notwithstanding
anything contained in this Agreement to the contrary, except as provided in the
following sentence, nothing in this Agreement, expressed or implied, is
intended to confer on any person other than the parties hereto or their
respective heirs, successors, executors, administrators and assigns any rights,
remedies, obligations or liabilities under or by reason of this Agreement. The
provisions of Article IV and Sections 7.11, 7.12, 7.13, 7.14 and 7.15
(collectively, the "Third Party Provisions") shall benefit the persons
identified therein, but the aggregate liability of AIP with respect thereto
shall not exceed the amount specified in Article IX.

       10.4.  Entire Agreement.  This Agreement, the Exhibits, the RELP
Disclosure Letter, the AIP Disclosure Letter, the RELP Ancillary Agreements,
the AIP Ancillary Agreements and any documents delivered by the parties in
connection herewith constitute the entire agreement among the parties with
respect to the subject matter hereof and supersede all prior agreements and
understandings among the parties with respect thereto. No addition to or
modification of any provision of this Agreement shall be binding upon any party
hereto unless made in writing and signed by all parties hereto.

       10.5.  Confidentiality.  (a)  As used herein, "Confidential Material"
means, with respect to either party hereto (the "Providing Party"), all
information (written or oral) furnished (whether before or after the date
hereof) by the Providing Party and its directors, officers, employees,
affiliates or representatives of advisors, including counsel, lenders and
financial advisors (collectively, the "Providing Party Representatives") to the
other party hereto (the "Receiving Party") or such Receiving Party's directors,
officers, employees, affiliates or representatives of advisors, including
counsel, lenders and financial advisors or the Receiving Party's potential
sources of financing for the transactions contemplated by this Agreement
(collectively "the Receiving Party Representatives") and all analyses,
compilations, forecasts and other studies or other documents prepared by the
Providing Party or the Providing Party Representatives in connection with its
or their review of the transactions contemplated by this Agreement which
contain or reflect such information. The term "Confidential Material" does not
include, however, information which (i) at the time of disclosure or thereafter
is generally available to and known by the public other than as a result of a
disclosure directly or indirectly by the Receiving Party or the Receiving Party
Representatives in violation of this Agreement, (ii) at the time of disclosure
was available on a nonconfidential basis from a source other than the Providing
Party or the Providing Party Representatives, providing that such source is not
and was not bound by a confidentiality agreement with the Providing Party,
(iii) was known by the Receiving Party prior to receiving the Confidential
Material from the Providing Party or has been independently acquired or
developed by the Receiving Party without violating any of its obligations under
this Agreement, or (iv) is contained in any RELP Reports or AIP Reports or
Proxy Statement/Prospectus.

       (b)    Subject to paragraph (c) below or except as required by law, the
Confidential Material will be kept confidential and will not, without the prior
written consent of the Providing Party, be disclosed by the Receiving Party or
its Representatives, in whole or in part and will not be used by the Receiving
Party or its Representatives, directly or indirectly, for any purpose other
than in





                                       33
<PAGE>   34
connection with this Agreement, the Merger or the evaluating, negotiating or
advising with respect to a transaction contemplated herein. Moreover, each
Receiving Party agrees to transmit Confidential Material to its Representatives
only if and to the extent that such Representatives need to know the
Confidential Material for purposes of such transaction and are informed by such
Receiving Party of the confidential nature of the Confidential Material and of
the terms of this Section.

       (c)    In the event that either Receiving Party, its Representatives or
anyone to whom such Receiving Party or its Representatives supply the
Confidential Material, are requested or required (by oral questions,
interrogatories, requests for information or documents, subpoena, civil
investigative demand, any informal or formal investigation by any government or
governmental agency or authority or otherwise in connection with legal
processes) to disclose any Confidential Material, such Receiving Party agrees
(i) to immediately notify the Providing Party of the existence, terms and
circumstances surrounding such a request, (ii) to consult with the Providing
Party on the advisability of taking legally available steps to resist or narrow
such request and (iii) if disclosure of such information is required, to
furnish only that portion of the Confidential Material which, in the opinion of
such Receiving Party's counsel, such Receiving Party is legally compelled to
disclose and to cooperate with any action by the Providing Party to obtain an
appropriate protective order or otherwise reliable assurances that confidential
treatment will be accorded the Confidential Material (it being agreed that the
Providing Party shall reimburse the Receiving Party for all reasonable out-of-
pocket expenses incurred by the Receiving Party in connection with such
cooperation).

       (d)    In the event of the termination of this Agreement in accordance
with its terms, promptly upon request from either Providing Party, the
Receiving Party shall, except to the extent prevented by law, redeliver to the
Providing Party or destroy all tangible Confidential Material and will not
retain any copies, extracts or other reproductions thereof in whole or in part.
Any such destruction shall be certified in writing to the Providing Party by an
authorized officer of the Receiving Party supervising the same. Notwithstanding
the foregoing, each Receiving Party and one Representative designated by each
Receiving Party shall be permitted to retain one permanent file copy of each
document constituting Confidential Material.

       (e)    Each party hereto further agrees that if this Agreement is
terminated in accordance with its terms, until one year from the date of
termination, (1) it will not offer to hire or hire any person currently or
formerly employed by the other party with whom such party has had contact prior
hereto other than persons whose employment shall have been terminated by such
other party prior to the date of such offer to hire or hiring and (2) neither
it nor its affiliates shall directly or indirectly, (a) (w) solicit, seek or
offer to effect or effect, (x) negotiate with or provide any information to the
Board of Trust Managers or General Partner, as applicable, of the other party,
or officer of the other party or any shareholder or partner, as applicable, of
the other party with respect to, (y) make any statement or proposal, whether
written or oral, either alone or in concert with others, to the Board of Trust
Managers or Board of Directors of the General Partner of the other party, any
director, Trust Manager or officer of the other party or any shareholder or
partner of the other party or any other person with respect to, or (z) make any
public announcement (except as required by law in respect of actions permitted
hereby) or proposal or offer whatsoever (including, but not limited to, any
"solicitation"of "proxies"as such terms are defined or used in Regulation 14A
of the Exchange Act) with respect to, (i) any form of business combination or
similar or other extraordinary transaction involving the other party or any
affiliate thereof, including, without limitation, a merger, tender or





                                       34
<PAGE>   35
exchange offer or liquidation of the other party's assets, (ii) any form of
restructuring, recapitalization or similar transaction with respect to the
other party or any affiliate thereto, (iii) any purchase of any securities or
assets, or rights or options to acquire any securities or assets (through
purchase, exchange, conversion or otherwise), of the other party or any
affiliate thereof, (iv) any proposal to seek representation on the Board of
Trust Managers or the Board of Directors of the General Partner, as applicable,
or otherwise to seek to control or influence the management, Board of Trust
Managers or the Board of Directors of the General Partner, as applicable, or
policies of the other party or any affiliate thereof, (v) any request or
proposal to waive, terminate or amend the provisions of this Section 10.5 or
(vi) any proposal or other statement inconsistent with the terms of this
Section 10.5 or (b) instigate, encourage, join, act in concert with or assist
(including, but not limited to, providing or assisting in any way in the
obtaining of financing for, or acting as a joint or co-bidder for the other
party with) any third party to do any of the foregoing, unless and until such
party has received the prior written invitation or approval of a majority of
the Board of Trust Managers or the General Partner, as applicable, to do any of
the foregoing; provided that without such invitation or approval, either party
may at any time, on a confidential non-public basis, submit to the Chief
Executive Officer of AIP or the General Partner, as applicable, a proposal to
(a) amend any of the provisions of this Section 10.5(e) or (b) effect a
business combination or other extraordinary transaction with the other party
providing for the acquisition of all or substantially all of the assets or the
securities of the other party, including, without limitation, a merger, tender
offer or exchange offer. Each party hereto agrees that it will not agree with
any third party to waive its rights under this Section 10.5.

       10.6.  Amendment.  This Agreement may be amended by the parties hereto,
by action taken by the Board of Trust Managers or the Board of Directors of the
General Partner, as applicable, at any time before or after approval of this
Agreement or any other matter presented in connection with the Merger by the
shareholders of AIP and partners of RELP, but after any such approval, no
amendment shall be made which by law requires the further approval of
shareholders or partners, as applicable, without obtaining such further
approval. This Agreement may not be amended except by an instrument in writing
signed on behalf of each of the parties hereto.

       10.7.  Governing Law.  This Agreement shall be governed by and construed
in accordance with the laws of the State of Texas without regard to its rules
of conflict of laws. Each of AIP and RELP hereby irrevocably and
unconditionally consents to submit to the exclusive jurisdiction of the courts
of the State of Texas and of the United States District Court, Northern
District of Texas (the "Texas Courts") for any litigation arising out of or
relating to this Agreement and the transactions contemplated hereby (and agrees
not to commence any litigation relating thereto except in such courts), waives
any objection to the laying of venue of any such litigation in the Texas Courts
and agrees not to plead or claim in any Texas Court that such litigation
brought therein has been brought in an inconvenient forum.

       10.8.  Counterparts.  This Agreement may be executed by the parties
hereto in separate counterparts, each of which when so executed and delivered
shall be an original, but all such counterparts shall together constitute one
and the same instrument. Each counterpart may consist of a number of copies
hereof each signed by less than all, but together signed by all of the parties
hereto.





                                       35
<PAGE>   36
       10.9.  Headings.  Heading of the Articles and Sections of this Agreement
are for the convenience of the parties only and shall be given no substantive
or interpretive effect whatsoever.

       10.10. Interpretation.  In this Agreement, unless the context otherwise
requires, words describing the singular number shall include the plural and
vice versa, and words denoting any gender shall include all genders and words
denoting natural persons shall include corporations and partnerships and vice
versa.

       10.11. Waivers.  Except as provided in this Agreement, no action taken 
pursuant to this Agreement, including, without limitation, any investigation by
or on behalf of any party, shall be deemed to constitute a waiver by the party
taking such action of compliance with any representations, warranties,
covenants or agreements contained in this Agreement. The waiver by any party
hereto of a breach of any provision hereunder shall not operate or be construed
as a waiver of any prior or subsequent breach of the same or any other
provision hereunder.

       10.12. Incorporation.  The RELP Disclosure Letter and the AIP Disclosure
Letter and all Exhibits and Schedules attached hereto and thereto and referred
to herein and therein are hereby incorporated herein and made a part hereof for
all purposes as if fully set forth herein.

       10.13. Severability.    If any provision of this Agreement is held to be
illegal, invalid or unenforceable under any current or future law, and if the
rights or obligations of the parties under this Agreement would not be
materially and adversely affected thereby, such provision shall be fully
separable, and this Agreement shall be construed and enforced as if such
illegal, invalid or unenforceable provision had never comprised a part thereof,
and the remaining provisions of this Agreement shall remain in full force and
effect and shall not be affected by the illegal, invalid or unenforceable
provision or by its severance therefrom.  In lieu of such illegal, invalid or
unenforceable provision, there shall be added automatically as a part of this
Agreement, a legal, valid and enforceable provision as similar in terms to such
illegal, invalid or unenforceable provision as may be possible, and the parties
hereto request the court or any arbitrator to whom disputes relating to this
Agreement are submitted to reform the otherwise illegal, invalid or
unenforceable provision in accordance with this Section 10.13.

       10.14. Enforcement of Agreement.  The parties hereto agree that 
irreparable damage would occur in the event that any of the provisions of this
Agreement was not performed in accordance with its specific terms or was
otherwise breached. It is accordingly agreed that the parties shall be entitled
to an injunction or injunctions to prevent breaches of this Agreement and to
enforce specifically the terms and provisions hereof in any Texas Court, this
being in addition to any other remedy to which they are entitled at law or in
equity.

       10.15. Subsidiaries.  As used in this Agreement, the word "Subsidiary" 
when used with respect to any party means any corporation, partnership, joint
venture, business trust or other entity, of which such party directly or
indirectly owns or controls at least a majority of the securities or other
interests having by their terms ordinary voting power to elect a majority of
the board of directors or others performing similar functions with respect to
such corporation or other organization.





                                       36
<PAGE>   37
       10.16.        Non-Recourse.  Neither the officers, Trust Managers nor
shareholders of AIP shall be personally bound or have any personal liability
hereunder. RELP shall look solely to the assets of AIP for satisfaction of any
liability of AIP with respect to this Agreement and the Ancillary Agreements to
which it is a party. RELP will not seek recourse or commence any action against
any of the shareholders of AIP or any of their personal assets, and will not
commence any action for money judgments against any of the Trust Managers or
officers of AIP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of AIP hereunder or thereunder. The
partners of RELP shall not be personally bound or have any personal liability
hereunder. AIP shall look solely to the assets of RELP for satisfaction of any
liability of RELP with respect to this Agreement and the Ancillary Agreements
to which it is a party. AIP will not seek recourse or commence any action
against any of the partners of RELP or any of their personal assets, and will
not commence any action for money judgments against any of the directors or
officers of RELP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of RELP hereunder or thereunder.

       IN WITNESS WHEREOF, the parties have executed this Agreement and caused
the same to be duly delivered on their behalf on the day and year first written
above.

                                AMERICAN INDUSTRIAL PROPERTIES REIT
                                
                                
                                /s/ Charles W. Wolcott               
                                --------------------------------
                                Charles W. Wolcott, President and
                                Chief Executive Officer
                                
                                
                                USAA REAL ESTATE INCOME
                                INVESTMENTS II LIMITED PARTNERSHIP

                                       By:   USAA INVESTORS II, INC.,           
                                             Its General Partner                
                                                                                
                                                                                
                                                                                
                                              /s/ T. Patrick Duncan             
                                              -----------------------           
                                              T. Patrick Duncan                 
                                              Senior Vice President - Operations





                                       37

<PAGE>   1
                                                                     EXHIBIT 2.3

                              AMENDED AND RESTATED
                          AGREEMENT AND PLAN OF MERGER

         THIS AMENDED AND RESTATED AGREEMENT AND PLAN OF MERGER (this
"Agreement"), dated as of June 30, 1997, is entered into by and between
American Industrial Properties REIT, a Texas real estate investment trust
("AIP") , and USAA Income Properties III Limited Partnership, a Delaware
limited partnership ("RELP").  USAA Real Estate Company, a Delaware corporation
("Realco"), is a party to this Agreement solely for the purpose of binding
itself to the provisions of Section 7.10 hereunder.

                                    RECITALS

         A.      The Board of Trust Managers of AIP (the "Board of Trust
Managers") and the general partner of RELP have each determined that a business
combination between AIP and RELP is in the best interests of their shareholders
and partners, respectively, and presents an opportunity for their respective
businesses to achieve strategic and financial benefits, and accordingly have
agreed to effect a merger subject to the terms and conditions set forth herein.

         B.      AIP and RELP desire to make certain representations,
warranties and agreements in connection with the merger.

         NOW, THEREFORE, in consideration of the foregoing, and of the
representations, warranties, covenants and agreements contained herein, AIP and
RELP hereby agree as follows:

                             ARTICLE I.  THE MERGER

         1.1.    The Merger. Subject to the terms and conditions of this
Agreement, at the Effective Time (as defined in Section 1.3), RELP shall be
merged with and into AIP in accordance with this Agreement and the Plan of
Merger (the "Plan of Merger") in substantially the form attached hereto as
Exhibit A, with such completions, additions and substitutions conforming to the
terms of this Agreement as the parties shall approve, such approval to be
conclusively evidenced by their causing the Plan of Merger containing such
completions, additions or substitutions to be filed in accordance with
applicable laws; and the separate existence of RELP shall thereupon cease (the
"Merger"). AIP shall be the surviving entity in the Merger (sometimes
hereinafter referred to as the "Survivor").  The Merger shall have the effects
specified in Section 23.60  of the Texas Real Estate Investment Trust Act, as
amended (the "Texas REIT Act") and Section 17-211 of the Delaware Revised
Uniform Limited Partnership Act (the "LP Act").

         1.2.    The Closing. Subject to the terms and conditions of this
Agreement, the closing of the Merger (the "Closing") shall take place at the
offices of Liddell, Sapp, Zivley, Hill & LaBoon, L.L.P. ("Liddell, Sapp"),
located at 2200 Ross Avenue, Suite 900, Dallas, Texas at 10:00 a.m., local
time, within five business days after receipt of approval of the Merger by
AIP's shareholders and RELP's partners, or at such other time, date or place as
AIP and RELP may agree. The date on which the Closing occurs is hereinafter
referred to as the "Closing Date."
<PAGE>   2
         1.3.    Effective Time. If all the conditions to the Merger set forth
in Article VIII shall have been fulfilled or waived (and this Agreement shall
not have been terminated as provided in Article IX), AIP and RELP shall cause
Articles of Merger satisfying the requirements of the Texas REIT Act and
Articles of Merger satisfying the requirements of the LP Act to be properly
executed, verified and delivered for filing in accordance with the LP Act and
the Texas REIT Act on the Closing Date. The Merger shall become effective for
accounting and all other purposes to the fullest extent permitted by law as of
the close of business on December 31, 1997 (the "Effective Time") or such other
date as may be agreed to by the parties. For state law purposes, the Merger
shall become effective upon the issuance of a certificate of merger by the
Secretary of State of the State of Delaware in accordance with the LP Act or at
such later time which AIP and RELP shall have agreed upon and designated in
such filings in accordance with applicable law.

                       ARTICLE II.  DECLARATION OF TRUST
                           AND BYLAWS OF THE SURVIVOR

         2.1.    Declaration of Trust.  The Declaration of Trust of AIP  in
effect immediately prior to the Effective Time shall be the Declaration of
Trust of the Survivor until duly amended in accordance with applicable law.

         2.2.    Bylaws.  The Bylaws of AIP in effect immediately prior to the
Effective Time shall be the Bylaws of the Survivor until duly amended in
accordance with applicable law.

                ARTICLE III.  TRUST MANAGERS AND OFFICERS OF AIP

         3.1.    Trust Managers.  The Trust Managers of AIP immediately prior
to the Effective Time shall be the Trust Managers of AIP as of the Effective
Time.

         3.2.     Officers.  The officers of AIP immediately prior to the
Effective Time shall be the officers of AIP as of the Effective Time.

                    ARTICLE IV.  RELP PARTNERSHIP  INTERESTS

         4.1.    Conversion of the RELP Partnership Interest.  (a)   At the
Effective Time, each Common Share of Beneficial Interest of AIP outstanding
immediately prior to the Effective Time shall remain outstanding and shall
represent one Common Share of Beneficial Interest of AIP.

         (b)     At the Effective Time, the general and limited partnership
interests of RELP  (each a  "RELP Interest"), issued and outstanding
immediately prior to the Effective Time shall, by virtue of the Merger and
without any action on the part of holder thereof, be converted into the right
to receive Common Shares of Beneficial Interest, $0.10 par value per share (the
"AIP Common Shares"), of AIP.  The aggregate number of AIP Common Shares to be
issued to the RELP partners in connection with the Merger shall be equal to
$24,300,000 (the "Purchase Price") divided by the Share Price (the "Total
Shares"). If, during the period from the date hereof to and including the
Closing Date, (i) the RELP pays any mortgage indebtedness existing on the date
hereof or (ii) the outstanding AIP Common Shares shall have been changed to a
different number of shares by reason




                                       2
<PAGE>   3
of any share dividend, subdivision, reclassification, recapitalization, share
split, reverse share split, combination, exchange of shares or the like, the
Purchase Price shall be appropriately adjusted.  The term "Share Price" shall
mean $2.625.  The number of AIP Common Shares to be received by a partner shall
be equal to the Total Shares multiplied by such partner's percentage interest
in RELP plus each limited partner's pro rata portion of the general partnership
interest of the RELP's general partner.

         (c)     As a result of the Merger and without any action on the part
of the holder thereof, at the Effective Time,  all RELP Interests  shall cease
to be outstanding and shall be canceled and retired, and each holder of a RELP
Interest shall thereafter cease to have any rights with respect to such RELP
Interest, except the right to receive, without interest, the AIP Common Shares
and cash for fractional shares of AIP Common Shares in accordance with Sections
4.1(b) and 4.2(e).

         4.2.    Exchange of RELP Interests.  (a)  As of the Effective Time,
AIP shall deposit, or shall cause to be deposited, with an exchange agent
selected by AIP, which shall be AIP's Transfer Agent or such other party
reasonably satisfactory to RELP (the "Exchange Agent"), for the benefit of the
holders of RELP Interests, for exchange in accordance with this Article IV,
certificates representing the Total Shares and the cash in lieu of fractional
shares (such cash and certificates for the Total Shares together with any
dividends or distributions with respect thereto, being hereinafter referred to
as the "Exchange Fund") to be issued pursuant to Section 4.1 and paid pursuant
to this Section 4.2 in exchange for outstanding RELP Interests.

         (b)     Promptly after the Effective Time, AIP shall cause the
Exchange Agent to mail to each holder of record of a RELP Interest (x) a
certificate representing the number of whole shares of AIP Common Shares and
(y) a check representing the amount of cash in lieu of fractional shares, if
any, and unpaid dividends and distributions, if any, which such holder has the
right to receive in respect of the RELP Interest surrendered pursuant to the
provisions of this Article IV, after giving effect to any required withholding
tax.  No interest will be paid or accrued on the cash in lieu of fractional
shares and unpaid dividends and distributions, if any, payable to holders of
RELP Interests.  In the event of a transfer of ownership of RELP Interests
which is not registered in the transfer records of RELP, a certificate
representing the proper number of AIP Common Shares, together with a check for
the cash to be paid in lieu of fractional shares, may be issued to such a
transferee if such holder presents to the Exchange Agent, all documents
required to evidence and effect such transfer and to evidence that any
applicable transfer taxes have been paid.

         (c)     At and after the Effective Time, there shall be no transfers
on the transfer books of RELP of RELP Interests which were outstanding
immediately prior to the Effective Time.

         (d)     No fractional AIP Common Shares shall be issued pursuant
hereto. In lieu of the issuance of any fractional AIP Common Shares pursuant to
Section 4.1(b), cash adjustments will be paid to holders in respect of any
fractional AIP Common Shares that would otherwise be issuable, and the amount
of such cash adjustment shall be equal to such fractional proportion of the
Share Price.





                                       3
<PAGE>   4
         (e)     Any portion of the Exchange Fund (including the proceeds of
any investments thereof and any AIP Common Shares) that remains unclaimed by
the former partners of RELP one year after the Effective Time shall be
delivered to AIP. Any former partners of RELP who have not theretofore complied
with this Article IV shall thereafter look only to AIP for delivery of their
AIP Common Shares, and payment of cash in lieu of fractional shares and unpaid
dividends and distributions on the AIP Common Shares deliverable in respect of
each RELP Interest such partners hold as determined pursuant to this Agreement,
in each case, without any interest thereon.

         (f)     None of AIP, RELP, the Exchange Agent or any other person
shall be liable to any former holder of RELP Interests for any amount properly
delivered to a public official pursuant to applicable abandoned property,
escheat or similar laws.


               ARTICLE V.  REPRESENTATIONS AND WARRANTIES OF RELP

         RELP represents and warrants to AIP as set forth below. As
contemplated below, a "RELP Disclosure Letter" will be delivered to AIP on or
before September 20, 1997.  The RELP Disclosure Letter shall provide the
information or exceptions described below and shall list all of the assets of
the RELP that will not be transferred in connection with the Merger. The RELP
Disclosure Letter shall be amended prior to Closing to cause such
representations and warranties to be materially true and correct on the Closing
Date, but RELP shall remain liable for any material breach of such
representations and warranties reflected in such amendment only as provided in
Section 9.5(d), below.

         5.1.    Existence; Good Standing; Authority; Compliance with Law.  (a)
RELP is a limited partnership,  duly formed, validly existing and in good
standing under the laws of the State of Delaware.  To its actual knowledge,
RELP is duly licensed or qualified to do business as a foreign limited
partnership and is in good standing under the laws of any other state of the
United States in which the character of the properties owned or leased by it
therein or in which the transaction of its business makes such qualification
necessary, except where the failure to be so qualified would not have a
material adverse effect on the business, results of operations or financial
condition of RELP (a "RELP Material Adverse Effect"). RELP has all requisite
power and authority to own, operate, lease and encumber its properties and
carry on its business as now conducted.

         (b)      To the RELP's actual knowledge, it is not in violation of any
order of any court, governmental authority or arbitration board or tribunal, or
any law, ordinance, governmental rule or regulation to which RELP or any of its
properties or assets is subject, where such violation would have a RELP
Material Adverse Effect. RELP has obtained all licenses, permits and other
authorizations and has taken all actions required by applicable law or
governmental regulations in connection with its business as now conducted,
where the failure to obtain any such item or to take any such action would have
a RELP Material Adverse Effect. A copy of RELP's Agreement of Limited
Partnership and Certificate of Limited Partnership (collectively, the "RELP
Organizational Documents") have been delivered or made available to AIP and its
counsel and such documents will be listed in the RELP Disclosure Letter and
were or will be true and correct when delivered or made available.





                                       4
<PAGE>   5
         5.2.    Authorization, Validity and Effect of Agreements.  RELP has
the requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions contemplated by this
Agreement (the "RELP Ancillary Agreements"). Subject only to the approval of
this Agreement and the transactions contemplated hereby in accordance with the
Agreement of Limited Partnership of the RELP, the consummation by RELP of this
Agreement, the RELP Ancillary Agreements and the transactions contemplated
hereby have been duly authorized by all requisite action on the part of RELP.
In reliance upon the legal opinion described in Section 8.2(e), RELP believes
this Agreement constitutes, and the RELP Ancillary Agreements (when executed
and delivered pursuant hereto for value received) will constitute, the valid
and legally binding obligations of RELP, enforceable against RELP in accordance
with their respective terms, subject to applicable bankruptcy, insolvency,
moratorium or other similar laws relating to creditors' rights and general
principles of equity (collectively, "Equitable Remedies").

         5.3.    Future Issuances.  To RELP's actual knowledge, there are not
at the date of this Agreement any existing options, warrants, calls,
subscriptions, convertible securities, or other rights, agreements or
commitments which obligate RELP to issue, transfer or sell any RELP Interests.
After the Effective Time, AIP will have no obligation to issue, transfer or
sell any RELP Interest.

         5.4.    Other Interests.  Except as set forth in the RELP Disclosure
Letter, RELP does not own directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

         5.5.    No Violation.  To RELP's actual knowledge, neither the
execution and delivery by RELP of this Agreement nor the consummation by RELP
of the transactions contemplated hereby in accordance with the terms hereof,
will: (i) conflict with or result in a breach of any provisions of the
Agreement of Limited Partnership of RELP; (ii) except as contemplated by the
RELP Ancillary Agreements or as will be set forth in the RELP Disclosure
Letter, violate, or conflict with, or result in a breach of any provision of,
or constitute a default (or an event which, with notice or lapse of time or
both, would constitute a default) under, or result in the termination or in a
right of termination or cancellation of, or accelerate the performance required
by, or result in the creation of any lien, security interest, charge or
encumbrance upon any of the properties of RELP under, or result in being
declared void, voidable or without further binding effect, any of the terms,
conditions or provisions of any note, bond, mortgage, indenture, deed of trust
or any license, franchise, permit, lease, contract, agreement or other
instrument, commitment or obligation to which RELP is a party, or by which RELP
or any of its  properties is bound or affected, except for any of the foregoing
matters which, individually or in the aggregate, would not have a RELP Material
Adverse Effect; or (iii) other than the filings provided for in Article I, any
filings required under the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), the Securities Act or applicable state securities and "Blue
Sky" laws (collectively, the "Regulatory Filings"), require any consent,
approval or authorization of, or declaration, filing or registration with, any
domestic governmental or regulatory authority, except where the failure to
obtain any such consent, approval or authorization of, or declaration, filing
or registration with, any governmental or regulatory authority would not have
an RELP Material Adverse Effect.





                                       5
<PAGE>   6
         5.6.    SEC Documents.  (a) RELP has made available or will make
available to AIP prior to September 30, 1997, each registration statement,
report, proxy statement or information statement and all exhibits thereto
prepared by it or relating to its properties (including registration statements
covering mortgage pass-through certificates) since January 1, 1994, each in the
form (including exhibits and any amendments thereto) filed with the SEC
(collectively, the "RELP Reports"). The RELP Reports, which were or will be
filed with the SEC in a timely manner, constitute all forms, reports and
documents required to be filed by RELP under the Securities Act of 1933, as
amended (the "Securities Act"), the Exchange Act and the rules and regulations
promulgated thereunder (collectively the "Securities Laws") for the periods
stated above.

         (b)     To the RELP's actual knowledge, as of their respective dates,
the RELP Reports (i) complied as to form in all material respects with the
applicable requirements of the Securities Laws and (ii) did not contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements made therein, in the
light of the circumstances under which they were made, not misleading. To the
RELP's actual knowledge, each of the balance sheets of RELP included in or
incorporated by reference into the RELP Reports (including the related notes
and schedules) fairly presents the financial position of RELP as of its date
and each of the consolidated statements of income, retained earnings and cash
flows of RELP included in or incorporated by reference into the RELP Reports
(including any related notes and schedules) fairly presents the results of
operations, retained earnings and cash flows, as the case may be, of RELP for
the periods set forth therein (subject, in the case of unaudited statements, to
normal year-end audit adjustments which would not be material in amount or
effect), in each case in accordance with generally accepted accounting
principles consistently applied during the periods involved, except as may be
noted therein and except, in the case of the unaudited statements, as permitted
by the Securities Laws.


         (c)     Except as and to the extent set forth on the balance sheet of
RELP at March 31, 1997, including all notes thereto, or as set forth in the
RELP Reports, RELP has no material liabilities or obligations of any nature
(whether accrued, absolute, contingent or otherwise) that would be required to
be reflected on, or reserved against in, a balance sheet of RELP or in the
notes thereto, prepared in accordance with generally accepted accounting
principles consistently applied, except liabilities arising in the ordinary
course of business since such date which would not have a RELP Material Adverse
Effect.

         5.7.    Litigation.  To the RELP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which RELP is a party or by which any of its
properties or assets are bound or to which USAA Properties III, Inc. (the
"General Partner")  or the General Partner's,  directors, officers, or
affiliates is a party or by which any of their properties or assets are bound,
and (ii) except as will be set forth in the RELP Disclosure Letter, no actions,
suits or proceedings pending against RELP or against the General Partner or the
General Partner's directors, officers or affiliates or, to the knowledge of the
General Partner, threatened against RELP or against the General Partner or the
General Partner's  directors, officers  or affiliates, at law or in equity, or
before or by any federal or state commission, board, bureau, agency or
instrumentality, that in the case of clauses (i) or (ii) above are reasonably
likely, individually or in the aggregate, to have a RELP Material Adverse
Effect.





                                       6
<PAGE>   7
         5.8.    Absence of Certain Changes.  Except as disclosed in the RELP
Reports filed prior to the date hereof, since March 31, 1997, (i) RELP
conducted its business only in the ordinary course of such business (which for
purposes of this section only, shall include all acquisitions of real estate
properties and financing arrangements made in connection therewith or otherwise
will be set forth in the RELP Disclosure Letter); (ii) there has not been any
RELP Material Adverse Effect; (iii) there has not been any distribution,
setting aside or payment of any distribution with respect to any RELP Interest,
and (iv) there has not been any material change in RELP's accounting
principles, practices or methods.

         5.9.    Taxes.  (a)  Except as may be set forth in the RELP Disclosure
Letter, RELP (i) has timely filed all federal, state and foreign tax returns
including, without limitation, information returns and reports required to be
filed by it for tax periods ended prior to the date of this Agreement or
requests for extensions have been timely filed and any such request has been
granted and has not expired and all such returns are accurate and complete in
all material respects, (ii) has paid or accrued all taxes shown to be due and
payable on such returns or which have become due and payable pursuant to any
assessment, deficiency notice, 30-day letter or other notice received by it and
(iii) has properly accrued all taxes for such periods and periods subsequent to
the periods covered by such returns. RELP has not received notice that the
federal, state and local income and franchise tax returns of RELP has been or
will be examined by any taxing authority. RELP has not executed or filed with
the Internal Revenue Service (the "IRS") or any other taxing authority any
agreement now in effect extending the period for assessment or collection of
any income or other taxes.

         (b)     Except as may be set forth in the RELP Disclosure Letter, RELP
is not  a party to any pending action or proceeding by any governmental
authority for assessment or collection of taxes, and no claim for assessment or
collection of taxes has been asserted against it. True, correct and complete
copies of all federal, state and local income or franchise tax returns filed by
RELP since January 1, 1991 and all communications relating thereto have been
delivered to AIP or made available to representatives of AIP or will be so
delivered or made available prior to September 30, 1997. RELP does not hold any
asset (i) the disposition of which could be subject to rules similar to Section
1374 of the Internal Revenue Code of 1986, as amended (the "Code") as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 5.9, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

         5.10.   Books and Records.  The books of account and other financial
records of RELP are in all material respects true, complete and correct, have
been maintained in accordance with good business practices, and are accurately
reflected in all material respects in the financial statements included in the
RELP Reports.

         5.11.   Properties.  (a)  RELP owns fee simple title to each of the
real properties reflected on the most recent balance sheet of RELP included in
the RELP Reports or as may be identified in the RELP Disclosure Letter (the
"RELP Properties"), which are all of the real estate properties owned by it,
free and clear of liens, mortgages or deeds of trust, claims against title,
charges which are liens or security interests ("Encumbrances") except as will
be noted in the RELP Disclosure Letter. To RELP's actual knowledge, the RELP
Properties are not subject to any rights of way, written agreements, laws,
ordinances and regulations affecting building use or occupancy, or reservations





                                       7
<PAGE>   8
of an interest in title (collectively, "Property Restrictions"), except for (i)
Encumbrances and Property Restrictions that will be set forth in the RELP
Disclosure Letter, (ii) Property Restrictions imposed or promulgated by law or
any governmental body or authority with respect to real property, including
zoning regulations, provided they do not materially adversely affect the
current use of the property, (iii) Encumbrances and Property Restrictions
disclosed on existing title reports or current surveys (in either case copies
of which title reports and surveys have been or will be delivered or made
available to AIP September 30, 1997), (iv) mechanics', carriers', workmen's,
repairmen's liens and other Encumbrances, Property Restrictions and other
limitations of any kind, if any, which have heretofore been bonded (and that
will be listed in the RELP Disclosure Letter) or which individually or in the
aggregate do not exceed $100,000, do not materially detract from the value of
or materially interfere with the present use of any of the RELP Properties
subject thereto or affected thereby, and do not otherwise materially impair
business operations conducted by RELP and which have arisen or been incurred
only in its construction activities or in the ordinary course of business.

         (b)     Valid policies of title insurance have been issued insuring
either (a) RELP's fee simple title to the RELP Properties or (b) first mortgage
liens thereon, subject only to the matters disclosed above and as may be set
forth in the RELP Disclosure Letter, and such policies are, at the date hereof,
in full force and effect and no claim has been made against any such policy. To
RELP's actual knowledge, except as will be set forth in the RELP Disclosure
Letter: (i) there is no certificate, permit or license from any governmental
authority having jurisdiction over any of the RELP Properties or any agreement,
easement or other right which is necessary to permit the lawful use and
operation of the buildings and improvements on any of the RELP Properties or
which is necessary to permit the lawful use and operation of all driveways,
roads and other means of egress and ingress to and from any of the RELP
Properties that has not been obtained and is not in full force and effect, or
of any pending threat of modification or cancellation of any of same; (ii) RELP
has not received written notice of any material violation of any federal, state
or municipal law, ordinance, order, regulation or requirement affecting any
portion of any of the RELP Properties issued by any governmental authority;
(iii) there are no structural defects relating to the RELP Properties and no
RELP Properties whose building systems are not in working order in any material
respect; and (iv) there is (A) no physical damage to any RELP Property in
excess of $100,000 for which there is no insurance in effect covering the cost
of the restoration, (B) no current renovation to any RELP Property the cost of
which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any RELP Property, the cost of which exceeds $100,000.

         (c)     Except as will be set forth in the RELP Disclosure Letter,
RELP has not received notice to the effect that and there are no (A)
condemnation or rezoning proceedings that are pending or threatened with
respect to any of the RELP Properties or (B) zoning, building or similar laws,
codes, ordinances, orders or regulations that are or will be violated by the
continued maintenance, operation or use of any buildings or other improvements
on any of the RELP Properties or by the continued maintenance, operation or use
of the parking areas. All work to be performed, payments to be made and actions
to be taken by RELP prior to the date hereof pursuant to any agreement





                                       8
<PAGE>   9
entered into with a governmental body or authority in connection with a site
approval, zoning reclassification or other similar action relating to the RELP
Properties (e.g., Local Improvement District, Road Improvement District,
Environmental Mitigation) has been performed, paid or taken, as the case may
be, and RELP is not aware of any planned or proposed work, payments or actions
that may be required after the date hereof pursuant to such agreements, except
as will be set forth in the RELP Disclosure Letter.

         5.12.   Environmental Matters.  To RELP's actual knowledge, RELP has
not  caused (i) the unlawful presence of any hazardous substances, hazardous
materials, toxic substances or waste materials (collectively, "Hazardous
Materials") on any of the RELP Properties, or (ii) any unlawful spills,
releases, discharges or disposal of Hazardous Materials to have occurred or be
presently occurring on or from the RELP Properties as a result of any
construction on or operation and use of such properties, which presence or
occurrence would, individually or in the aggregate, have a RELP Material
Adverse Effect; and in connection with the construction on or operation and use
of the RELP Properties, RELP has not failed to comply, in any material respect,
with any applicable local, state and federal environmental laws, regulations,
ordinances and administrative and judicial orders relating to the generation,
recycling, reuse, sale, storage, handling, transport and disposal of any
Hazardous Materials.

         5.13.   Labor Matters.  RELP is not a party to, or bound by, any
collective bargaining agreement, contract or other agreement or understanding
with a labor union or labor union organization. There is no unfair labor
practice or labor arbitration proceeding pending or, to the knowledge of the
General Partner, threatened against RELP relating to its business, except for
any such proceeding which would not have a RELP Material Adverse Effect. To the
knowledge of the General Partner, there are no organizational efforts with
respect to the formation of a collective bargaining unit presently being made
or threatened involving employees of RELP or any of its Subsidiaries.

         5.14.    No Brokers.  Except the fee that is to be paid to Houlihan
Lokey Howard & Zukin ("Houlihan")  by RELP as described in Section 5.15 below,
RELP has not entered into any contract, arrangement or understanding with any
person or firm which may result in the obligation of RELP or AIP to pay any
finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby. RELP is not aware of any claim for
payment of any finder's fees, brokerage or agent's commissions or other like
payments in connection with the negotiations leading to this Agreement or the
consummation of the transactions contemplated hereby.

         5.15.    Opinion of Financial Advisor.  RELP has retained Houlihan to
review the transaction contemplated by this Agreement and to issue an opinion
to the effect that, as of the date of such opinion, the Purchase Price is fair
to the holders of RELP Interests from a financial point of view.

         5.16.    Related Party Transactions.  Except as set forth in the RELP
Disclosure Letter, there are no arrangements, agreements or contracts entered
into by RELP with (i) any consultant, (ii) any person who is an officer,
director or affiliate of RELP or its General Partner, any relative of any of
the foregoing or any entity of which any of the foregoing is an affiliate, or
(iii) any person who acquired RELP Interests in a private placement.





                                       9
<PAGE>   10
         5.17.    Contracts and Commitments.  The RELP Disclosure Letter will
set forth (i) all unsecured notes or other obligations of RELP which
individually may result in total payments in excess of $100,000, (ii) all
notes, debentures, bonds and other evidence of indebtedness which are secured
or collateralized by mortgages, deeds of trust or other security interests in
the RELP Properties or personal property of RELP,  and (iii) each commitment
entered into by RELP which may result in total payments or liability in excess
of $100,000. Copies of the foregoing will be delivered or made available to AIP
prior to September 30, 1997, will be listed on the RELP Disclosure Letter and
will be materially true and correct when delivered or made available. RELP has
not received any notice of a default that has not been cured under any of the
documents described in clause (i) above or is in default respecting any payment
obligations thereunder beyond any applicable grace periods. All options of RELP
to purchase real property will be set forth on the RELP Disclosure Letter and
such options and RELP's rights thereunder are in full force and effect. All
joint venture agreements to which RELP is a party will be set forth on the RELP
Disclosure Letter and RELP is not in default with respect to any obligations,
which individually or in the aggregate are material, thereunder.

         5.18.    Development Rights.  Set forth in the RELP Disclosure Letter
will be a list of all material agreements entered into by RELP relating to the
development, rehabilitation, capital improvement or construction of office
buildings, industrial facilities  or other real estate properties, which
development or construction has not been substantially completed as of the date
of this Agreement. Such agreements, true and correct copies of all of which
will be delivered or made available to AIP prior to September 30, 1997, will be
listed in the RELP Disclosure Letter, have not been modified and are valid and
binding in accordance with their respective terms.

         5.19.    Convertible Securities.  To RELP's actual knowledge, RELP has
no outstanding options, warrants or other securities exercisable for, or
convertible into, RELP Interests, the terms of which would require any anti-
dilution adjustments by reason of the consummation of the transactions
contemplated hereby.

              ARTICLE VI .  REPRESENTATIONS AND WARRANTIES OF AIP

         AIP represents and warrants to RELP as set forth below.  As
contemplated below, an "AIP Disclosure Letter" will be delivered to RELP on or
before September 20, 1997.  The AIP Disclosure Letter shall provide the
information or exceptions described below. The AIP Disclosure Letter shall be
amended prior to Closing to cause such representations and warranties to be
materially true and correct on the Closing Date, but AIP shall remain liable
for any material breach of such representations and warranties reflected in
such amendment only as provided in Section 9.5(d), below.

         6.1.     Existence; Good Standing; Authority; Compliance with Law.
(a)  AIP is a real estate investment trust duly organized and  validly existing
under the laws of the State of Texas.   To AIP's actual knowledge, AIP is duly
licensed or qualified to do business and is in good standing under the laws of
any other state of the United States in which the character of the properties
owned or leased by it therein or in which the transaction of its business makes
such qualification necessary, except where the failure to be so qualified would
not have a material adverse effect on the business, results of operations or
financial condition of AIP and its subsidiaries taken as a whole (an "AIP
Material





                                       10
<PAGE>   11
Adverse Effect"). AIP has all requisite power and authority to own, operate,
lease and encumber its properties and carry on its business as now conducted.
Each of AIP's Subsidiaries is a corporation, limited liability company or
partnership duly organized, validly existing and in good standing under the
laws of its jurisdiction of incorporation or organization, has the requisite
power and authority to own its properties and to carry on its business as it is
now being conducted, and is duly qualified to do business and is in good
standing in each jurisdiction in which the ownership of its property or the
conduct of its business requires such qualification, except for jurisdictions
in which such failure to be so qualified or to be in good standing would not
have an AIP Material Adverse Effect.

         (b)     To AIP's actual acknowledge, neither AIP nor any AIP
Subsidiary is in violation of any order of any court, governmental authority or
arbitration board or tribunal, or any law, ordinance, governmental rule or
regulation to which AIP or any AIP Subsidiary or any of their respective
properties or assets is subject, where such violation would have an AIP
Material Adverse Effect. AIP and its Subsidiaries have obtained all licenses,
permits and other authorizations and have taken all actions required by
applicable law or governmental regulations in connection with their business as
now conducted, where the failure to obtain any such item or to take any such
action would have an AIP Material Adverse Effect. Copies of AIP's and its
Subsidiaries' Declaration of Trust, Articles of Incorporation, Bylaws,
organizational documents and partnership and joint venture agreements have been
or will be prior to September 30, 1997, delivered or made available to RELP and
such documents will be listed in the AIP Disclosure Letter and were or will be
true and correct when delivered or made available. For the purposes of the
immediately preceding sentence, the term "Subsidiary"shall include the entities
set forth in AIP's Disclosure Letter,  which are all of AIP's Subsidiaries.

         6.2.     Authorization, Validity and Effect of Agreements.  AIP has
the requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions contemplated by this
Agreement to which it is a party (the "AIP Ancillary Agreements"). Subject only
to the approval of the issuance of AIP Common Shares pursuant to the Merger
contemplated hereby by the holders of two-thirds of the outstanding AIP Common
Shares, present and voting thereon, the consummation by AIP of this Agreement,
the AIP Ancillary Agreements and the transactions contemplated hereby have been
duly authorized by all requisite action on the part of AIP. This Agreement
constitutes, and the AIP Ancillary Agreements (when executed and delivered
pursuant hereto for value received) will constitute, the valid and legally
binding obligations of AIP enforceable against AIP in accordance with their
respective terms, subject to Equitable Remedies.

         6.3.     Capitalization.  On June 15, 1997, the authorized capital
stock of AIP consists of 10,000,000 Common Shares. As of the date hereof, all
10,000,000 Common Shares are outstanding. AIP has no outstanding bonds,
debentures, notes or other obligations (other than to Realco), the holders of
which have the right to vote (or which are convertible into or exercisable for
securities having the right to vote) with the shareholders of AIP on any
matter. Except as set forth in the AIP Disclosure Letter, all such issued and
outstanding of AIP Common Shares are duly authorized, validly issued, fully
paid, nonassessable and free of preemptive rights. Except as set forth in the
AIP Disclosure Letter, there are not at the date of this Agreement any existing
options, warrants, calls, subscriptions, convertible securities, or other
rights, agreements or commitments which obligate AIP or any of its Subsidiaries
to issue, transfer or sell any shares or other equity interest of AIP or any





                                       11
<PAGE>   12
of its Subsidiaries except under any employee incentive plan approved by AIP's
shareholders. There are no agreements or understandings to which AIP is a party
with respect to the voting of any AIP Common Shares or which restrict the
transfer of any such shares, except in order to protect its REIT status.

         6.4.    Subsidiaries.  Except as set forth in the AIP Disclosure
Letter, AIP owns directly or indirectly each of the outstanding shares of
capital stock or all of the partnership or other equity interests of each of
AIP's Subsidiaries free and clear of all liens, pledges, security interests,
claims or other encumbrances other than liens imposed by local law which are
not material.

         6.5.    Other Interests.   Except as will be disclosed in the AIP
Disclosure Letter and except for interests in the AIP Subsidiaries, neither AIP
nor any AIP Subsidiary owns directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

         6.6.    No Violation.   Neither the execution and delivery by AIP of
this Agreement nor the consummation by AIP of the transactions contemplated
hereby in accordance with the terms hereof, will: (i) conflict with or result
in a breach of any provisions of AIP's Declaration of Trust; (ii) violate, or
conflict with, or result in a breach of any provision of, or constitute a
default (or an event which, with notice or lapse of time or both, would
constitute a default) under, or result in the termination or in a right of
termination or cancellation of, or accelerate the performance required by, or
result in the creation of any lien, security interest, charge or encumbrance
upon any of the properties of AIP or its Subsidiaries under, or result in being
declared void, voidable or without further binding effect, any of the terms,
conditions or provisions of any note, bond, mortgage, indenture, deed of trust
or any license, franchise, permit, lease, contract, agreement or other
instrument, commitment or obligation to which AIP or any of its Subsidiaries is
a party, or by which AIP or any of its Subsidiaries or any of their properties
is bound or affected, except for any of the foregoing matters which,
individually or in the aggregate, would not have an AIP Material Adverse
Effect; or (iii) other than the Regulatory Filings require any consent,
approval or authorization of, or declaration, filing or registration with, any
domestic governmental or regulatory authority, except where the failure to
obtain such consent, approval or authorization of, or declaration, filing or
registration with, any governmental or regulatory authority would not have an
AIP Material Adverse Effect.

         6.7.    SEC Documents.   (a)  AIP has made available or will make
available to RELP prior to September 30, 1997, the registration statements of
AIP filed with the SEC in connection with public offerings of AIP securities
since January 1, 1994 and all exhibits, amendments and supplements thereto (the
"AIP Registration Statements"), and each registration statement, report, proxy
statement or information statement and all exhibits thereto prepared by it or
relating to its properties since the effective date of the latest AIP
Registration Statement, each in the form (including exhibits and any amendments
thereto) filed with the SEC (collectively, the "AIP Reports"). The AIP Reports,
which were or will be filed with the SEC in a timely manner, constitute all
forms, reports and documents required to be filed by AIP under the Securities
Laws.





                                       12
<PAGE>   13
         (b)     To AIP's actual knowledge, as of their respective dates, the
AIP Reports (i) complied as to form in all material respects with the
applicable requirements of the Securities Laws, and (ii) did not contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements made therein, in the
light of the circumstances under which they were made, not misleading. To AIP's
actual acknowledge, each of the consolidated balance sheets of AIP included in
or incorporated by reference into the AIP Reports (including the related notes
and schedules) fairly presents the consolidated financial position of AIP and
the AIP Subsidiaries as of its date and each of the consolidated statements of
income, retained earnings and cash flows of AIP included in or incorporated by
reference into the AIP Reports (including any related notes and schedules)
fairly presents the results of operations, retained earnings or cash flows, as
the case may be, of AIP and the AIP Subsidiaries for the periods set forth
therein (subject, in the case of unaudited statements, to normal year-end audit
adjustments which would not be material in amount or effect), in each case in
accordance with generally accepted accounting principles consistently applied
during the periods involved, except as may be noted therein and except, in the
case of the unaudited statements, as permitted by the Securities Laws.

         (c)     Except as and to the extent set forth on the consolidated
balance sheet of AIP and its Subsidiaries at March 31, 1997, including all
notes thereto, or as set forth in the AIP Reports, neither AIP nor any of the
AIP Subsidiaries has any material liabilities or obligations of any nature
(whether accrued, absolute, contingent or otherwise) that would be required to
be reflected on, or reserved against in, a balance sheet of AIP or in the notes
thereto, prepared in accordance with generally accepted accounting principles
consistently applied, except liabilities arising in the ordinary course of
business since such date which would not have an AIP Material Adverse Effect.

         6.8.     Litigation.   To AIP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which AIP or any AIP Subsidiary is a party or by
which any of its properties or assets are bound or, to which any of its
directors, officers, or affiliates is a party or by which any of their
properties or assets are bound, and (ii) except as will be set forth in the AIP
Disclosure Letter, no actions, suits or proceedings pending against AIP or any
AIP Subsidiary or, to the knowledge of AIP, against any of its Trust Managers,
officers, or affiliates or, to the knowledge of AIP, threatened against AIP or
any AIP Subsidiary or against any of its Trust Managers, officers, or
affiliates, at law or in equity, or before or by any federal or state
commission, board, bureau, agency or instrumentality, that in the case of
clauses (i) or (ii) above are reasonably likely, individually or in the
aggregate, to have an AIP Material Adverse Effect.

         6.9.     Absence of Certain Changes.  Except as disclosed in the AIP
Reports filed with the SEC prior to the date hereof, (i) AIP and its
Subsidiaries have conducted their business only in the ordinary course of such
business (which, for purposes of this section only, shall include all
acquisitions of real estate properties and financing arrangements made in
connection therewith); (ii) there has not been any AIP Material Adverse Effect;
(iii) there has not been any declaration, setting aside or payment of any
dividend or other distribution with respect to the AIP Common Shares; and (iv)
there has not been any material change in AIP's accounting principles,
practices or methods.





                                       13
<PAGE>   14
         6.10.    Taxes.  (a)  Except as may be set forth in the AIP Disclosure
Letter, AIP and each of its Subsidiaries (i) has timely filed all federal,
state and foreign tax returns including, without limitation, information
returns and reports required to be filed by any of them for tax periods ended
prior to the date of this Agreement or requests for extensions have been timely
filed and any such request has been granted and has not expired and all such
returns are absolute and complete in all material respects, (ii) has paid or
accrued all taxes shown to be due and payable on such returns or which have
become due and payable pursuant to any assessment, deficiency notice, 30-day
letter or other notice received by it and (iii) has properly accrued all taxes
for such periods subsequent to the periods covered by such returns. Neither AIP
nor any of its Subsidiaries has received notice that the federal, state and
local income and franchise tax returns of AIP or any such Subsidiary has been
or will be examined by any taxing authority. Neither AIP nor any of its
Subsidiaries has executed or filed with the IRS or any other taxing authority
any agreement now in effect extending the period for assessment or collection
of any income or other taxes.

         (b)     Except as will be disclosed in the AIP Disclosure Letter,
neither AIP nor any of its Subsidiaries is a party to any pending action or
proceeding by any governmental authority for assessment or collection of taxes,
and no claim for assessment or collection of taxes has been asserted against
it. True, correct and complete copies of all federal, state and local income or
franchise tax returns filed by AIP and each of its Subsidiaries and all
communications relating thereto have been delivered to RELP or made available
to representatives of RELP or will be so delivered or made available prior to
September 30, 1997. AIP (i) has qualified to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable years ended December 31,
1985 through 1996, inclusive (ii) has operated, and intends to continue to
operate, in such a manner as to qualify to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable year ended on the
effective date of the Merger, and (iii) has not taken or omitted to take any
action which could result in, and each of the executive officers of AIP, each
acting in his respective capacity as such, has no actual knowledge of, a
challenge to its status as a REIT. AIP represents that each of its Subsidiaries
is a Qualified REIT Subsidiary as defined in Section 856 (i) of the Code.
Neither AIP nor any of its Subsidiaries holds any asset (i) the disposition of
which could be subject to rules similar to Section 1374 of the Code as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 6.10, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

         6.11.   Books and Records.  (a)  The books of account and other
financial records of AIP and its Subsidiaries are in all material respects
true, complete and correct, have been maintained in accordance with good
business practices, and are accurately reflected in all material respects in
the financial statements included in the AIP Reports.

         (b)     The minute books and other records of AIP and its Subsidiaries
contain in all material respects accurate records of all meetings and
accurately reflect in all material respects all other corporate action of the
shareholders and Trust Managers and any committees of the Board of Trust
Managers of AIP and its Subsidiaries.





                                       14
<PAGE>   15
         6.12.    Properties.  (a)  AIP and its Subsidiaries own fee simple
title to each of the real properties reflected on the most recent balance sheet
of AIP included in the AIP Reports or as may be identified in the AIP
Disclosure Letter (the "AIP Properties"), which are all of the real estate
properties owned by them, free and clear of Encumbrances. To AIP's actual
knowledge, the AIP Properties are not subject to any rights of way, written
agreements, laws, ordinances and regulations affecting building use or
occupancy, or reservations of an interest in title (collectively, "Property
Restrictions"), except for (i) Encumbrances and Property Restrictions that will
be set forth in the AIP Disclosure Letter, (ii) Property Restrictions imposed
or promulgated by law or any governmental body or authority with respect to
real property, including zoning regulations, provided they do not materially
adversely affect the current use of the property, (iii) Encumbrances and
Property Restrictions disclosed on existing title reports or surveys (in either
case copies of which title reports and surveys have been or will be delivered
or made available to RELP prior to September 30, 1997), and (iv) mechanics',
carriers', workmen's, repairmen's liens and other Encumbrances, Property
Restrictions and other limitations of any kind, if any, which have heretofore
been bonded (and that will be listed in the AIP Disclosure Letter) or which
individually or in the aggregate, do not exceed $100,000, do not materially
detract from the value of or materially interfere with the present use of any
of the AIP Properties subject thereto or affected thereby, and do not otherwise
materially impair business operations conducted by AIP and its Subsidiaries and
which have arisen or been incurred only in its construction activities or in
the ordinary course of business.

         (b)     Valid policies of title insurance have been issued insuring
AIP's or any of its Subsidiaries' fee simple title to the AIP Properties,
subject only to the matters disclosed above and as may be set forth in the AIP
Disclosure Letter, and such policies are, at the date hereof, in full force and
effect and no material claim has been made against any such policy. To AIP's
actual knowledge, except as will be set forth in the AIP Disclosure Letter, (i)
there is no certificate, permit or license from any governmental authority
having jurisdiction over any of the AIP Properties or any agreement, easement
or other right which is necessary to permit the lawful use and operation of the
buildings and improvements on any of the AIP Properties or which is necessary
to permit the lawful use and operation of all driveways, roads and other means
of egress and ingress to and from any of the AIP Properties that has not been
obtained and is not in full force and effect, or of any pending threat of
modification or cancellation of any of same; (ii) neither AIP nor its
Subsidiaries has received written notice of any material violation of any
federal, state or municipal law, ordinance, order, regulation or requirement
affecting any portion of any of the AIP Properties issued by any governmental
authority; (iii) there are no structural defects relating to the AIP Properties
and no AIP Properties whose building systems are not in working order in any
material respect; and (iv) there is (A) no physical damage to any AIP Property
in excess of $100,000 for which there is no insurance in effect covering the
cost of the restoration, (B) no current renovation to any AIP Property the cost
of which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any AIP Property the cost of which exceeds $100,000.

         (c)     Except as will be set forth in the AIP Disclosure Letter, AIP
or its Subsidiaries have received no notice to the effect that and there are no
(A) condemnation or rezoning proceedings that are pending or threatened with
respect to any of the AIP Properties or (B) any zoning, building or similar
laws, codes, ordinances, orders or regulations that are or will be violated by
the continued maintenance, operation or use of any buildings or other
improvements on any of the AIP Properties or by the continued maintenance,
operation or use of the parking areas in any material respect. All





                                       15
<PAGE>   16
work to be performed, payments to be made and actions to be taken by AIP or its
Subsidiaries prior to the date hereof pursuant to any agreement entered into
with a governmental body or authority in connection with a site approval,
zoning reclassification or other similar action relating to the AIP Properties
(e.g., Local Improvement District, Road Improvement District, Environmental
Mitigation) has been performed, paid or taken, as the case may be, and AIP is
not aware of any planned or proposed work, payments or actions that may be
required after the date hereof pursuant to such agreements, except as will be
set forth in the AIP Disclosure Letter.

         6.13.   Environmental Matters.  To the actual knowledge of AIP, none
of AIP, any of its Subsidiaries or, any other person has caused or permitted
(i) the unlawful presence of any Hazardous Materials on any of the AIP
Properties, or (ii) any unlawful spills, releases, discharges or disposal of
Hazardous Materials to have occurred or be presently occurring on or from the
AIP Properties as a result of any construction on or operation and use of such
properties, which presence or occurrence would, individually or in the
aggregate, have an AIP Material Adverse Effect; and in connection with the
construction on or operation and use of the AIP Properties, AIP and its
Subsidiaries have not failed to comply, in any material respect, with any
applicable local, state and federal environmental laws, regulations, ordinances
and administrative and judicial orders relating to the generation, recycling,
reuse, sale, storage, handling, transport and disposal of any Hazardous
Materials.

         6.14.   Labor Matters.   Neither AIP nor any of its Subsidiaries is a
party to, or bound by, any collective bargaining agreement, contract or other
agreement or understanding with a labor union or labor union organization.
There is no unfair labor practice or labor arbitration proceeding pending or,
to the knowledge of the executive officers of AIP, threatened against AIP or
its Subsidiaries relating to their business, except for any such proceeding
which would not have an AIP Material Adverse Effect. To the knowledge of AIP,
there are no organizational efforts with respect to the formation of a
collective bargaining unit presently being made or threatened involving
employees of AIP or any of its Subsidiaries.

         6.15.   No Brokers.  Except for the fee payable to Prudential
Securities Incorporated ("Prudential") as described in Section 6.16 below, AIP
has not entered into any contract, arrangement or understanding  with any
person or firm which may result in the obligation of AIP or RELP to pay any
finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby. AIP is not aware of any claim for
payment of any finder's fees, brokerage or agent's commissions or other like
payments in connection with the negotiations leading to this Agreement or the
consummation of the transactions contemplated hereby.

         6.16.   Opinion of Financial Advisor.  AIP has retained Prudential to
review the transaction contemplated by this Agreement and to issue an opinion
as to the fairness to AIP, from a financial point of view, of the consideration
to be paid by AIP pursuant to the Merger.

         6.17.   RELP Share Ownership.  Except as may be set forth in the AIP
Disclosure Letter, neither AIP nor any of its Subsidiaries owns any RELP
Interests or other securities convertible into RELP interests.





                                       16
<PAGE>   17
         6.18.    AIP Common Shares.  The issuance and delivery by AIP of AIP
Common Shares in connection with the Merger and this Agreement have been duly
and validly authorized by all necessary action on the part of AIP except for
the approval of its shareholders contemplated by this Agreement. The AIP Common
Shares to be issued in connection with the Merger and this Agreement, when
issued in accordance with the terms of this Agreement, will be validly issued,
fully paid and nonassessable, except that shareholders may be subject to
further assessment with respect to certain claims for tort, contract, taxes,
statutory liability and otherwise in some jurisdictions to the extent such
claims are not satisfied by AIP.

         6.19.   Convertible Securities.  AIP has no outstanding options,
warrants or other securities exercisable for, or convertible into, shares of
AIP Common Shares, the terms of which would require any anti-dilution
adjustments by reason of the consummation of the transactions contemplated
hereby, except the preemptive rights held by certain clients of Morgan Stanley
Asset Management, Inc. and held by MS Real Estate Special Situations, Inc. and
the convertible debt securities held by Realco.

         6.20.   Related Party Transactions.  Set forth in the AIP Disclosure
Letter will be a list of all arrangements, agreements and contracts entered
into by AIP or any of its Subsidiaries with (i) any person who is an officer,
Trust Manager or affiliate of AIP or any of its Subsidiaries, any relative of
any of the foregoing or any entity of which any of the foregoing is an
affiliate or (ii) any person who acquired AIP Common Shares in a private
placement. The copies of such documents, all of which have been or will be
delivered or made available to RELP prior to September 30, 1997, are or will be
true, complete and correct when delivered or made available.

         6.21.   Contracts and Commitments.  The AIP Disclosure Letter will set
forth (i) all unsecured notes or other obligations of AIP and AIP Subsidiaries
which individually may result in total payments in excess of $100,000, (ii)
notes, debentures, bonds and other evidence of indebtedness which are secured
or collateralized by mortgages, deeds of trust or other security interests in
the AIP Properties or personal property of AIP and its Subsidiaries, and (iii)
each commitment entered into by AIP or any of its Subsidiaries which
individually may result in total payments or liability in excess of $100,000.
Copies of the foregoing have been or will be delivered or made available to
RELP prior to September 30, 1997, will be listed on the AIP Disclosure Letter
and are or will be materially true and correct when delivered or made
available. None of AIP or any of its Subsidiaries has received any notice of a
default that has not been cured under any of the documents described in clause
(i) or (ii) above or is in default respecting any payment obligations
thereunder beyond any applicable grace periods. All options of AIP or any of
its Subsidiaries to purchase real property will be set forth on the AIP
Disclosure Letter and such options and AIP's or its Subsidiaries' rights
thereunder are in full force and effect. All joint venture agreements to which
AIP or any of its Subsidiaries is a party will be set forth on the AIP
Disclosure Letter and AIP or its Subsidiaries are not in default with respect
to any obligations, which individually or in the aggregate are material,
thereunder.

         6.22.   Development Rights.  Set forth in the AIP Disclosure Letter
will be a list of all material agreements entered into by AIP or any of its
Subsidiaries relating to the development, rehabilitation, capital improvement
or construction of office buildings, industrial facilities or other real estate
properties which development or construction has not been substantially
completed as of





                                       17
<PAGE>   18
the date of this Agreement. Such agreements, true, complete and correct copies
of all of which have been or will be delivered or made available to RELP prior
to September 30, 1997, will be listed in the AIP Disclosure Letter.

         6.23.   Certain Payments Resulting From Transactions.  The execution
of, and performance of the transactions contemplated by, this Agreement will
not (either alone or upon the occurrence of any additional or subsequent
events) (i) constitute an event under any AIP Benefit Plan, policy, practice,
agreement or other arrangement or any trust or loan (the "Employee
Arrangements") that will or may result in any payment (whether of severance pay
or otherwise), acceleration, forgiveness of indebtedness, vesting,
distribution, increase in benefits or obligation to fund benefits with respect
to any employee, director or consultant of AIP or any of its Subsidiaries
unless such rights have been waived by any such person, or (ii) result in the
triggering or imposition of any restrictions or limitations on the right of AIP
or RELP to amend or terminate any Employee Arrangement and receive the full
amount of any excess assets remaining or resulting from such amendment or
termination, subject to applicable taxes. No payment or benefit which will be
required to be made pursuant to the terms of any agreement, commitment or AIP
Benefit Plan, as a result of the transactions contemplated by this Agreement,
to any officer, director or employee of AIP or any of its Subsidiaries, will be
characterized as an "excess parachute payment" within the meaning of Section
280G(b)(1) of the Code.

                            ARTICLE VII.  COVENANTS

         7.1.    Acquisition Proposals.   Prior to the Effective Time, RELP and
AIP each agree (i) that neither of them nor any of their Subsidiaries shall,
and each of them shall direct and use its best efforts to cause its respective
officers, General Partner, limited partners, Trust Managers, employees, agents,
affiliates and representatives (including, without limitation, any investment
banker, attorney or accountant retained by it or any of its Subsidiaries), as
applicable, not to, initiate, solicit or encourage, directly or indirectly, any
inquiries or the making or implementation of any proposal or offer (including,
without limitation, any proposal or offer to its shareholders) with respect to
a merger, acquisition, tender offer, exchange offer, consolidation or similar
transaction involving, or any purchase of all or any significant portion of the
assets or any equity securities (or any debt securities convertible into equity
securities) of, such party or any of its Subsidiaries, other than the
transactions contemplated by this Agreement (any such proposal or offer being
hereinafter referred to as an "Acquisition Proposal") or engage in any
negotiations concerning, or provide any confidential information or data to, or
have any discussions with, any person relating to an Acquisition Proposal, or
otherwise facilitate any effort or attempt to make or implement an Acquisition
Proposal; (ii) that it will immediately cease and cause to be terminated any
existing activities, discussions or negotiations with any parties conducted
heretofore with respect to any of the foregoing and each will take the
necessary steps to inform the individuals or entities referred to above of the
obligations undertaken in this Section 7.1; and (iii) that it will notify the
other party immediately if any such inquiries or proposals are received by, any
such information is requested from, or any such negotiations or discussions are
sought to be initiated or continued with, it; provided, however, that nothing
contained in this Section 7.1 shall prohibit the Board of Directors of the
General Partner of RELP (the "Board of Directors") or the Board of Trust
Managers from (x) furnishing information to or entering into discussions or
negotiations with, any person or entity that makes an unsolicited bona fide
Acquisition Proposal, if, and only to the extent that, (A) the Board





                                       18
<PAGE>   19
of Directors or Board of Trust Managers, as applicable, determines in good
faith that such action is required for it to comply with its fiduciary duties
to limited partners or shareholders, as applicable,  imposed by law as advised
by counsel, (B) prior to furnishing such information to, or entering into
discussions or negotiations with, such person or entity, such party provides
written notice to the other party to this Agreement to the effect that it is
furnishing information to, or entering into discussions with, such person or
entity, and (C) subject to any confidentiality agreement with such person or
entity (which such party determined in good faith was required to be executed
in order for the Board of Directors or Board of Trust Managers, as applicable,
to comply with its fiduciary duties to limited partners or shareholders, as
applicable,  imposed by law as advised by counsel), such party keeps the other
party to this Agreement informed of the status (but not the terms) of any such
discussions or negotiations; and (y) to the extent applicable, complying with
Rule 14e-2 promulgated under the Exchange Act with regard to an Acquisition
Proposal.

         Nothing in this Section 7.1 shall (i) permit any party to terminate
this Agreement (except as specifically provided in Article IX hereof), (ii)
permit any party to enter into any agreement with respect to an Acquisition
Proposal during the term of this Agreement (it being agreed that during the
term of this Agreement, no party shall enter into any agreement with any person
that provides for, or in any way facilitates, an Acquisition Proposal (other
than a confidentiality agreement in customary form)), or (iii) affect any other
obligation of any party under this Agreement.

         7.2.    Conduct of Businesses.

         (i)      Prior to the Effective Time, except as may be set forth in
the RELP Disclosure Letter or the AIP Disclosure Letter or as contemplated by
this Agreement, unless the other party has consented in writing thereto, AIP
and RELP:

         (a)     Shall use their reasonable efforts, and shall cause each of
                 their respective Subsidiaries to use their reasonable efforts,
                 to preserve intact their business organizations and goodwill
                 and keep available the services of their respective officers
                 and employees;

         (b)     Shall confer on a regular basis with one or more
                 representatives of the other to report operational matters of
                 materiality and, subject to Section 7.1, any proposals to
                 engage in material transactions;

         (c)     Shall promptly notify the other of any material emergency or
                 other material change in the condition (financial or
                 otherwise) of the  business, properties, assets or
                 liabilities, or any material governmental complaints,
                 investigations or hearings (or communications indicating that
                 the same may be contemplated), or the breach in any material
                 respect of any representation, warranty, covenant or agreement
                 contained herein;

         (d)     Shall not pay quarterly dividends or make distributions
                 payable with respect to the AIP Common Shares and RELP
                 Partnership Interests, respectively; and

         (e)     Shall promptly deliver to the other true and correct copies of
                 any report, statement or schedule filed with the SEC
                 subsequent to the date of this Agreement.





                                       19
<PAGE>   20
         (ii)    Prior to the Effective Time, except as may be set forth in the
RELP Disclosure Letter, unless AIP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, RELP:

         (a)      Shall conduct its operations according to its usual, regular
                 and ordinary course in substantially the same manner as
                 heretofore conducted;

         (b)     Shall not amend the RELP Organizational Documents;

         (c)     Shall not (i) except pursuant to the exercise of options,
                 warrants, conversion rights and other contractual rights
                 existing on the date hereof and disclosed pursuant to this
                 Agreement, issue any RELP Interests, make any distribution,
                 effect any recapitalization or other similar transaction, (ii)
                 grant, confer or award any option, warrant, conversion right
                 or other right not existing on the date hereof to acquire any
                 RELP Interest, (iii) increase any compensation or enter into
                 or amend any employment agreement with any of its present or
                 future officers or directors of the General Partner, or (iv)
                 adopt any new employee benefit plan or amend any existing
                 employee benefit plan in any material respect, except for
                 changes which are less favorable to participants in such
                 plans;

         (d)     Shall not declare, set aside or make any distribution or
                 payment with respect to any RELP Interest or directly or
                 indirectly redeem, purchase or otherwise acquire any RELP
                 Interest, or make any commitment for any such action;

         (e)     Shall not sell or otherwise dispose of (i) any RELP
                 Properties, or (ii) except in the ordinary course of business,
                 any of its other assets which are material, individually or in
                 the aggregate;

         (f)     Shall not make any loans, advances or capital contributions
                 to, or investments in, any other person;

         (g)     Shall not pay, discharge or satisfy any claims, liabilities or
                 obligations (absolute, accrued, asserted or unasserted,
                 contingent or otherwise), other than the payment, discharge or
                 satisfaction in the ordinary course of business consistent
                 with past practice or in accordance with their terms, of
                 liabilities reflected or reserved against in, or contemplated
                 by, the most recent consolidated financial statements (or the
                 notes thereto) of RELP included in the RELP Reports or
                 incurred in the ordinary course of business consistent with
                 past practice;

         (h)     Shall not enter into any commitment which individually may
                 result in total payments or liability by or to it in excess of
                 $250,000 in the case of any one commitment or in excess of
                 $500,000 for all commitments;





                                       20
<PAGE>   21
         (i)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment with any officer, director or
                 affiliate of RELP or  its General Partner except to the extent
                 the same occur in the ordinary course of business consistent
                 with past practice and would not have a RELP Material Adverse
                 Effect; and

         (j)     Shall not enter into or terminate any lease representing
                 annual revenues of $100,000 or more.

         (iii)   Prior to the Effective Time, except as may be set forth in the
AIP Disclosure Letter, unless RELP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, AIP:

         (a)     Shall, and shall cause each of its Subsidiaries to, conduct
                 its operations according to their usual, regular and ordinary
                 course in substantially the same manner as heretofore
                 conducted;

         (b)     Shall not amend its Declaration of Trust or Bylaws except as
                 contemplated by this Agreement;

         (c)     Shall not (i) except pursuant to the exercise of options,
                 warrants, conversion rights and other contractual rights
                 (including AIP's existing dividend reinvestment plan) existing
                 on the date hereof and disclosed pursuant to this Agreement,
                 issue any shares of its capital stock, effect any share split,
                 reverse share split, share dividend, recapitalization or other
                 similar transaction, (ii) grant, confer or award any option,
                 warrant, conversion right or other right not existing on the
                 date hereof to acquire any shares of its capital shares
                 (except pursuant to any employee incentive plan approved by
                 shareholders), (iii) amend any employment agreement with any
                 of its present or future officers or Trust Managers, or (iv)
                 adopt any new employee benefit plan (including any share
                 option, share benefit or share purchase plan) except the
                 employee incentive plan to be voted on at its shareholder
                 meeting for the fiscal year ended December 31, 1995;

         (d)     Shall not declare, set aside or pay any dividend or make any
                 other distribution or payment with respect to any Common
                 Shares or directly or indirectly redeem, purchase or otherwise
                 acquire  any Common Shares or capital stock of any of its
                 Subsidiaries, or make any commitment for any such action;

         (e)     Except as will be set forth in the AIP Disclosure Letter,
                 shall not, and shall not permit any of its Subsidiaries to,
                 sell or otherwise dispose of (i) any AIP Properties or any of
                 its capital stock of or other interests in Subsidiaries or
                 (ii) except in the ordinary course of business, any of its
                 other assets which are material, individually or in the
                 aggregate;

         (f)     Shall not, and shall not permit any of its Subsidiaries to,
                 make any loans, advances or capital contributions to, or
                 investments in, any other person other than in connection with
                 the sale of properties;





                                       21
<PAGE>   22
         (g)     Shall not, and shall not permit any of its Subsidiaries to,
                 pay, discharge or satisfy any claims, liabilities or
                 obligations (absolute, accrued, asserted or unasserted,
                 contingent or otherwise), other than the payment, discharge or
                 satisfaction in the ordinary course of business consistent
                 with past practice or in accordance with their terms, of
                 liabilities reflected or reserved against in, or contemplated
                 by, the most recent consolidated financial statements (or the
                 notes thereto) of AIP included in the AIP Reports or incurred
                 in the ordinary course of business consistent with past
                 practice;

         (h)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment which individually may result in
                 total payments or liability by or to it in excess of $500,000
                 in the case of any one commitment or in excess of $500,000 for
                 all commitments; and

         (i)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment with any officer, Trust Manager or
                 affiliate of AIP or any of its Subsidiaries, except as herein
                 or in the AIP Disclosure Letter provided and except in the
                 ordinary course of business.

For purposes of this Section 7.2, any consent shall be deemed to be
unreasonably delayed if notice of consent or withholding of consent is not
received within three days of request.  Further, if no response is received by
the end of business on such third day, the party receiving the request shall be
deemed to have consented to such action.

         7.3     Meetings of Shareholders and Partners.  Each of AIP and RELP
will take all action necessary in accordance with applicable law and its
organizational documents  to convene a meeting of its shareholders or partners,
as applicable,  as promptly as practicable to consider and vote upon or
otherwise to obtain the consent of its shareholders or partners, as applicable,
to (i) in the case of AIP, approve this Agreement and the transactions
contemplated hereby, and (ii) in the case of RELP, approve this Agreement and
the transactions contemplated hereby. The Board of Trust Managers and the
General Partner shall each recommend such approval and AIP and RELP shall each
take all lawful action to solicit such approval, including, without limitation,
timely mailing the Proxy Statement/Prospectus (as defined in Section 7.7);
provided, however, that such recommendation or solicitation is subject to any
action taken by, or upon authority of, the Board of Trust Managers or the
General Partner, as the case may be, in the exercise of its good faith judgment
as to its fiduciary duties to its shareholders or partners, as applicable,
imposed by law as advised by counsel. AIP and RELP shall coordinate and
cooperate with respect to the timing of such meetings and shall use their best
efforts to hold such meetings on the same day.

         7.4.     Filings; Other Action.  Subject to the terms and conditions
herein provided, RELP and AIP shall: (a) use all reasonable efforts to
cooperate with one another in (i) determining which filings are required to be
made prior to the Effective Time with, and which consents, approvals, permits
or authorizations are required to be obtained prior to the Effective Time from
governmental or regulatory authorities of the United States and the several
states in connection with the execution and delivery of this Agreement and the
consummation of the transactions contemplated hereby and (ii) timely making all
such filings and timely seeking all such consents, approvals, permits or
authorizations; (b) use all reasonable efforts to obtain in writing any
consents required from third





                                       22
<PAGE>   23
parties in form reasonably satisfactory to RELP and AIP necessary to effectuate
the Merger; and (c) use all reasonable efforts to take, or cause to be taken,
all other action and do, or cause to be done, all other things necessary,
proper or appropriate to consummate and make effective the transactions
contemplated by this Agreement. If, at any time after the Effective Time, any
further action is necessary or desirable to carry out the purpose of this
Agreement, the proper officers and directors of AIP and the General Partner
shall take all such necessary action.

         7.5.    Inspection of Records.  From the date hereof to the Effective
Time, each of RELP and AIP shall allow all designated officers, attorneys,
accountants and other representatives of the other access at all reasonable
times to the records and  files, correspondence, audits and properties, as well
as to all information relating to commitments, contracts, titles and financial
position, or otherwise pertaining to the business and affairs of RELP and AIP
and their respective Subsidiaries.

         7.6.    Publicity.  RELP and AIP shall, subject to their respective
legal obligations (including requirements of stock exchanges and other similar
regulatory bodies), consult with each other, and use reasonable efforts to
agree upon the text of any press release before issuing any such press release
or otherwise making public statements with respect to the transactions
contemplated hereby and in making any filings with any federal or state
governmental or regulatory agency or with any national securities exchange with
respect thereto.

         7.7.    Registration Statement.  AIP and RELP shall cooperate and
promptly prepare and AIP shall file with the SEC as soon as practicable a
Registration Statement on Form S-4 (the "Form S-4") under the Securities Act,
with respect to the AIP Common Shares issuable in the Merger, a portion of
which Registration Statement shall also serve as the joint proxy statement with
respect to the meetings of the shareholders and partners, respectively, of AIP
and RELP in connection with the Merger (the "Proxy Statement/Prospectus"). The
respective parties will cause the Proxy Statement/Prospectus and the Form S-4
to comply as to form in all material respects with the applicable provisions of
the Securities Act, the Exchange Act and the rules and regulations promulgated
thereunder. AIP shall use all reasonable efforts, and RELP will cooperate with
AIP to have the Form S-4 declared effective by the SEC as promptly as
practicable.  AIP shall use its best efforts to obtain, prior to the effective
date of the Form S-4, all necessary state securities law or "Blue Sky" permits
or approvals required to carry out the transactions contemplated by this
Agreement and will pay all expenses incident thereto. AIP agrees that the Proxy
Statement/Prospectus and each amendment or supplement thereto, at the time of
mailing thereof and at the time of the respective meetings of shareholders and
partners, respectively, of AIP and RELP, or, in the case of the Form S-4 and
each amendment or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading; provided, however, that the foregoing shall not apply to the
extent that any such untrue statement of a material fact or omission to state a
material fact was made by AIP in reliance upon and in conformity with written
information concerning RELP furnished to AIP by RELP specifically for use in
the Proxy Statement/Prospectus. RELP agrees that the written information
provided by it specifically for inclusion in the Proxy Statement/Prospectus and
each amendment or supplement thereto, at the time of mailing thereof and at the
time of the respective meetings of shareholders and partners, respectively, of
AIP and RELP, or, in the case of written information provided by RELP
specifically for inclusion in the Form S-4





                                       23
<PAGE>   24
or any amendments or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading. AIP will advise RELP, promptly after it receives notice
thereof, of the time when the Form S-4 has become effective or any supplement
or amendment has been filed, the issuance of any stop order, the suspension of
the qualification of the AIP Common Shares issuable in connection with the
Merger for offering or sale in any jurisdiction, or any request by the SEC for
amendment of the Proxy Statement/Prospectus or the Form S-4 or comments thereon
and responses thereto or requests by the SEC for additional information.

         7.8.    Listing Application.  AIP shall promptly prepare and submit to
the NYSE a listing application covering the AIP Common Shares issuable in the
Merger, and shall use its reasonable efforts to obtain, prior to the Effective
Time, approval for the listing of such AIP Common Shares, subject to official
notice of issuance.

         7.9.    Further Action.  Each party hereto shall, subject to the
fulfillment at or before the Effective Time of each of the conditions of
performances set forth herein or the waiver thereof, perform such further acts
and execute such documents as may reasonably be required to effect the Merger.

         7.10.   Expenses.  Subject to Section 9.5, if the Merger is approved
by RELP's partners, all transaction costs of the proposed consolidation shall
be paid by AIP.  If three of the four limited partnerships party to the Proxy
Statement/Prospectus (the "Other RELPS") do not approve their proposed merger
into AIP, Realco shall reimburse AIP for AIP's expenses relating to the
proposed merger up to $250,000.  If RELP and the Other RELPS approve their
proposed merger into AIP, but the shareholders of AIP do not approve the
proposer merger, and if Realco voted its AIP Common Shares in favor of such
mergers, AIP will reimburse RELP and the Other RELPS for all expenses they
incurred in connection with the proposed merger.  Any expenses to be reimbursed
hereunder shall include, but not be limited to, costs of fairness opinions,
property appraisals, engineering and environmental reports, title policies,
accounting fees, legal fees, printing and solicitation expenses.  RELP will
bear the costs of preparing its initial fairness opinion, with later
reimbursement by AIP in the event the Merger is approved by RELP's partners.
If the limited partners of RELP fail to approve the proposed Merger, then
Realco will reimburse AIP for the RELP's expenses (to the extent paid by AIP)
as follows: the actual cost of such RELP's fairness opinion, legal fees up to
$80,000, and the actual cost or the Allocable Share  (if the actual cost is not
separately determined), of RELP's accounting fees, engineering and
environmental reports, printing and solicitation expenses.  Allocable Share,
for this purpose, shall be the ratio of such RELP's net book value of assets at
March 31, 1997 to the total net book value of all of the assets of RELP and the
Other RELPS at March 31, 1997.

         7.11.   Indemnification.  For a period of six years from and after the
Effective Time, AIP shall indemnify the partners, or agents of RELP who at any
time prior to the Effective Time were entitled to indemnification under the
Agreement of Limited Partnership of RELP existing on the date hereof to the
same extent as such partners or agents are entitled to indemnification under
such Agreement of Limited Partnership in respect of actions or omissions
occurring at or prior to the Effective Time (including, without limitation, the
transactions contemplated by this Agreement).





                                       24
<PAGE>   25
         7.12.   REIT Status.  From and after the date and until the Effective
Time, neither AIP nor RELP nor any of their respective Subsidiaries or other
affiliates shall (i) knowingly take any action, or knowingly fail to take any
action, that would jeopardize qualification of AIP as a REIT within the meaning
of Sections 856 through 859 of the Code; or (ii) enter into any contract,
agreement, commitment or arrangement with respect to the foregoing.

         7.13.   Survival of RELP Obligations; Assumption of RELP Liabilities
by AIP.  All of the obligations of RELP that are outstanding at the Closing
shall survive the Closing and shall not be merged therein. Upon the
consummation of the Merger, such obligations shall be assumed, automatically,
by AIP; provided, however, that such assumption shall not impose upon or expose
AIP to any liability for which RELP was not liable, and provided, further, that
AIP shall be entitled to the same defenses, offsets and counterclaims to which
RELP would have been entitled, but for the Merger.

         7.14.   Third Party Consents.  AIP and RELP each shall take all
necessary corporate and other action and will use its commercially reasonable
efforts to obtain the consents and applicable approvals from third parties that
may be required to enable it to carry out the transactions contemplated by this
Agreement.

         7.15.   Efforts to Fulfill Conditions.  AIP and RELP each shall use
commercially reasonable efforts to insure that all conditions precedent to its
obligations hereunder are fulfilled at or prior to the Closing.

         7.16.   Representations, Warranties and Conditions Prior to Closing.
AIP and RELP each shall use its commercially reasonable efforts to cause its
representations and warranties contained in this Agreement to be true and
correct on and as of the Closing Date in all material respects. Prior to
Closing, AIP and RELP each shall promptly notify the other in writing (i) if
any representation or warranty contained in this Agreement is discovered to be
or becomes untrue or (ii) if AIP or RELP fails to perform or comply with any of
its covenants or agreements contained in this Agreement or it is reasonably
expected that it will be unable to perform or comply with any of its covenants
or agreements contained in this Agreement.

         7.17.   Cooperation of the Parties.  AIP and RELP each will cooperate
with the other in supplying such information as may be reasonably requested by
the other in connection with obtaining consents or approvals to the
transactions contemplated by this Agreement.

         7.18.   Lock-Ups.  The General Partner shall use its best efforts
prior to the Closing to have each of its directors and officers and Realco
execute a 90-day lock-up agreement in a form (reasonably acceptable to RELP)
supplied to RELP by AIP. The executed agreements will be delivered to AIP at
the Closing.  AIP shall use its best efforts prior to the Closing to have each
of its Trust Managers and officers execute a 90-day lock-up agreement, in a
form (reasonably acceptable to AIP) supplied to AIP by RELP. The agreements
will be delivered to RELP at the Closing.





                                       25
<PAGE>   26
                           ARTICLE VIII.  CONDITIONS

         8.1.    Conditions to Each Party's Obligations to Effect the Merger.
The respective obligation of each party to effect the Merger shall be subject
to the fulfillment at or prior to the Closing Date of the following conditions:

         (a)     This Agreement and the transactions contemplated hereby shall
                 have been approved in the manner required by the Declaration
                 of Trust  and Bylaws and Agreement of Limited Partnership of
                 AIP and RELP, respectively, and by applicable law or by
                 applicable regulations of any stock exchange or other
                 regulatory body by the holders of the AIP Common Shares and
                 RELP Interests entitled to vote thereon.

         (b)     Neither of the parties hereto shall be subject to any order or
                 injunction of a court of competent jurisdiction which
                 prohibits the consummation of the transactions contemplated by
                 this Agreement. In the event any such order or injunction
                 shall have been issued, each party agrees to use its
                 reasonable efforts to have any such injunction lifted.

         (c)     The Form S-4 shall have become effective and all necessary
                 state securities law or "Blue Sky" permits or approvals
                 required to carry out the transactions contemplated by this
                 Agreement shall have been obtained and no stop order with
                 respect to any of the foregoing shall be in effect.

         (d)     AIP shall have obtained the approval for the listing of the
                 AIP Common Shares issuable in the Merger on the NYSE, subject
                 to official notice of issuance.

         (e)     All consents, authorizations, orders and approvals of (or
                 filings or registrations with) any governmental commission,
                 board, other regulatory body or third parties required in
                 connection with the execution, delivery and performance of
                 this Agreement shall have been obtained or made, except for
                 filings in connection with the Merger and any other documents
                 required to be filed after the Effective Time and except where
                 the failure to have obtained or made any such consent,
                 authorization, order, approval, filing or registration would
                 not have a material adverse effect on the business, results of
                 operations or financial condition of AIP and RELP (and their
                 respective Subsidiaries), taken as a whole, following the
                 Effective Time.

         8.2     Conditions to Obligations of RELP to Effect the Merger.  The
obligation of RELP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by
RELP:

         (a)     AIP shall have performed its agreements contained in this
                 Agreement required to be performed on or prior to the Closing
                 Date and the representations and warranties of AIP contained
                 in this Agreement shall be true and correct in all material
                 respects as of the Closing Date as if made on the Closing
                 Date, and RELP shall have received a certificate of the
                 President or an Executive or Senior Vice President of AIP,
                 dated the Closing Date, certifying to such effect.





                                       26
<PAGE>   27
         (b)     RELP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by AIP and approved by
                 RELP, dated the Closing Date, to the effect that AIP met the
                 requirements for qualification and taxation as a REIT for its
                 taxable year ending December 31, 1985, and has met the
                 requirements for qualification and taxation as a REIT for its
                 taxable years 1986 through 1996; AIP's diversity of equity
                 ownership, operations through the Closing Date and proposed
                 method of operation for future periods should allow it to
                 qualify as a REIT for its taxable year ending December 31,
                 1997; and the discussion contained under the caption "Material
                 Federal Income Tax Consequences" in the Proxy
                 Statement/Prospectus accurately reflects existing law and
                 fairly addresses the material Federal income tax issues
                 described therein.  In rendering its opinion, said counsel
                 shall be entitled to rely as to any factual matter upon
                 certificates given by executive officers and other duly
                 authorized representatives of RELP and AIP and shall be
                 entitled to assume that the covenants set forth in Article VII
                 shall be fully complied with.

         (c)     From the date of the Agreement through the Effective Time,
                 there shall not have occurred any change in the financial
                 condition, business or operations of AIP and its Subsidiaries,
                 taken as a whole, that would have or would be reasonably
                 likely to have an AIP Material Adverse Effect other than any
                 such change that affects both RELP and AIP in a substantially
                 similar manner.

         (d)     The opinion of Houlihan addressed to RELP that the Purchase
                 Price is fair, from a financial point of view, to the partners
                 of RELP shall not have been withdrawn or materially modified.

         (e)     RELP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by AIP and approved by
                 RELP, dated the Closing Date, as to such customary matters as
                 RELP may reasonably request, such opinion to be reasonably
                 satisfactory to RELP.

         8.3     Conditions to Obligation of AIP to Effect the Merger.  The
obligations of AIP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by AIP:

         (a)     RELP shall have performed its agreements contained in this
                 Agreement required to be performed on or prior to the Closing
                 Date and the representations and warranties of RELP contained
                 in this Agreement shall be true and correct in all material
                 respects as of the Closing Date as if made on the Closing Date
                 and AIP shall have received a certificate of the Chief
                 Executive Officer, President or an Executive Vice President of
                 the General Partner dated the Closing Date, certifying to such
                 effect.

         (b)     AIP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by RELP and approved by
                 AIP, dated the Closing Date, to the effect that the
                 consummation of the Merger will not result in AIP's failure to
                 continue to satisfy the





                                       27
<PAGE>   28
                 requirements for qualification as a REIT for federal income
                 tax purposes. In rendering its opinion, said counsel shall be
                 entitled to rely as to any factual matter upon certificates
                 given by executive officers and other duly authorized
                 representatives of AIP and RELP and shall be entitled to
                 assume that the covenants of Article VII shall be fully
                 complied with.

         (c)     From the date of this Agreement through the Effective Time,
                 there shall not have occurred any change in the financial
                 condition, business or operations of RELP and its
                 Subsidiaries, taken as a whole, that would have or would be
                 reasonably likely to have an RELP Material Adverse Effect,
                 other than any such change that affects both RELP and AIP in a
                 substantially similar manner.

         (d)     Each person listed on Exhibit 8.3(d) attached hereto shall
                 have delivered to AIP a written agreement to the effect that
                 such person will not offer to sell, sell or otherwise dispose
                 of any shares of AIP Common Stock issued in the Merger,
                 except, in each case, pursuant to an effective registration
                 statement or in compliance with Rule 145, as amended from time
                 to time, or in a transaction which, in the opinion of legal
                 counsel reasonably satisfactory to AIP, is exempt from the
                 registration requirements of the Securities Act and that the
                 certificates representing the AIP shares issued to him or her
                 in the Merger may bear a legend to such effect.

         (e)     The opinion of Prudential addressed to the Board of Trust
                 Managers of AIP that the consideration to be paid by AIP
                 pursuant to the Merger is fair, from a financial point of
                 view, to AIP shall not have been withdrawn or materially
                 modified.

         (f)     AIP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by RELP and approved by
                 AIP, dated the Closing Date, as to such customary matters as
                 AIP may reasonably request, such opinion to be reasonably
                 satisfactory to AIP.

         (g)     The limited partners of at least two of the Other RELPS shall
                 have approved the merger of such limited partnership with and
                 into AIP.

                            ARTICLE IX.  TERMINATION

         9.1     Termination by Mutual Consent.  This Agreement may be
terminated and the Merger may be abandoned at any time prior to the Effective
Time, before or after the approval of this Agreement by the partners of RELP or
the shareholders of AIP or by the mutual written consent of AIP and RELP, with
the prior approval of their respective Board of Trust Managers and General
Partner.

         9.2     Termination by Either AIP or RELP.  This Agreement may be
terminated and the Merger may be abandoned by action of the General Partner of
RELP or the Board of Trust Managers of AIP if (i) the Merger shall not have
been consummated by March 31, 1998, (ii) a meeting of RELP's partners shall
have been duly convened and held and the approval of RELP's partners required
by Section 8.1(a) shall not have been obtained at such meeting or at any
adjournment





                                       28
<PAGE>   29
thereof, (iii) a meeting of AIP's shareholders shall have been duly convened
and held and the approval of AIP's shareholders required by Section 8.1(a)
shall not have been obtained at such meeting or at any adjournment thereof,
(iv) as a result of due diligence investigation by one of the parties hereto,
it is determined in good faith by such party that certain facts or
circumstances not previously known by such party constitute a Material Adverse
Effect on the business, results of operations or financial condition of the
other party, (v) a United States federal or state court of competent
jurisdiction or United States federal or state governmental, regulatory or
administrative agency or commission shall have issued an order, decree or
ruling or taken any other action permanently restraining, enjoining or
otherwise prohibiting the transactions contemplated by this Agreement and such
order, decree, ruling or other action shall have become final and
non-appealable, provided that the party seeking to terminate this Agreement
pursuant to this clause (v) shall have used all reasonable efforts to remove
such order, decree, ruling or injunction, or (vi) any of the conditions set
forth in Article VIII shall not have been satisfied,  and provided, in the case
of a termination pursuant to clause (i) or (vi) above, that the terminating
party shall not have breached in any material respect its obligations under
this Agreement in any manner that shall have proximately contributed to the
occurrence of the failure referred to in said clause. AIP and RELP each shall
(i) deliver its Disclosure Letter to one another not later than 5:00 P.M.,
Central Time, September 20, 1997, and (ii) shall complete its due diligence
investigations not later than 5:00 P.M., Central Time, on September 30, 1997.
Until October 7, 1997 (the period from the date of this Agreement through
October 7, 1997 being hereinafter referred to as the "Due Diligence Period"),
either party may terminate this Agreement without liability or penalty due to
the discovery of a fact or circumstance that reasonably could be expected to
constitute a Material Adverse Effect on the business, results of operations or
financial condition of the other party.  Unless objected to by the party
receiving the Disclosure Letter in writing prior to the expiration of the Due
Diligence Period, the receiving party shall be deemed to have approved the
other party's Disclosure Letter.

         9.3      Termination by RELP.  This Agreement may be terminated and
the Merger may be abandoned at any time prior to the Effective Time, before or
after the adoption and approval by the partners of RELP referred to in Section
8.1(a), by action of the General Partner, if (i) in the exercise of its good
faith judgment as to its fiduciary duties to its partners imposed by law, as
advised by counsel, the General Partner determines that such termination is
required by reason of a RELP Acquisition Proposal being made, (ii) the Board of
Trust Managers withdraws, materially modifies or changes in a manner materially
adverse to RELP its recommendations to AIP's shareholders of this Agreement or
the Merger, other than as a result of the occurrence of an event that in the
good faith judgment of the Board of Trust Managers has or is reasonably likely
to have a RELP Material Adverse Effect, (iii) the Board of Trust Managers
postpones the date scheduled for the meeting of shareholders of AIP to approve
this Agreement and the transactions contemplated hereby beyond March 31, 1998
or fails to set a date for such meeting by such date, except with the written
consent of RELP, (iv) there has been a breach by AIP of any representation or
warranty contained in this Agreement which would have or would be reasonably
likely to have an AIP Material Adverse Effect, which breach is not curable by
March 31,1998, or (v) there has been material breach of any of the covenants or
agreements set forth in this Agreement on the part of AIP, which breach is not
curable or, if curable, is not cured within 30 days after written notice of
such breach is given by RELP to AIP, or (vi) the condition set forth in Section
8.3(g) is not satisfied.





                                       29
<PAGE>   30
         9.4     Termination by AIP.  This Agreement may be terminated and the
Merger may be abandoned at any time prior to the Effective Time, before or
after the approval by the shareholders of AIP referred to in Section 8.1(a), by
action of the Board of Trust Managers,  if (i) in the exercise of its good
faith judgment as to its fiduciary duties to its shareholders imposed by law,
as advised by counsel, the Board of Trust Managers determines that such
termination is required by reason of an AIP Acquisition Proposal being made,
(ii) the General Partner withdraws, materially modifies or changes in a manner
materially adverse to AIP its recommendation to RELP's partners of this
Agreement or the Merger, other than as a result of the occurrence of an event
that in the good faith judgment of the General Partner has or is reasonably
likely to have an AIP Material Adverse Effect, (iii) the General Partner
postpones the date scheduled for the meeting of partners of RELP to approve
this Agreement and the transactions contemplated hereby beyond March 31, 1998,
or fails to set a date for such meeting by such date, except with the written
consent of AIP, (iv) there has been a breach by RELP of any representation or
warranty contained in this Agreement which would have or would be reasonably
likely to have a RELP Material Adverse Effect, which breach is not curable by
March 31, 1998, or (v) there has been a material breach of any of the covenants
or agreements set forth in this Agreement on the part of RELP, which breach is
not curable or, if curable, is not cured within 30 days after written notice of
such breach is given by AIP to RELP.

         9.5.    Effect of Termination and Abandonment.  (a)  If an election to
terminate this Agreement is made pursuant to (i) Section 9.2(i) (except as a
result of a default or breach hereunder by AIP) or Section 9.2(ii), and a RELP
Acquisition Proposal relating to RELP shall have been made and, within one year
from the date of such termination, RELP consummates a RELP Acquisition Proposal
or enters into an agreement to consummate a RELP Acquisition Proposal which is
subsequently consummated, or (ii) Section 9.3(i), RELP shall pay to AIP,
provided that AIP was not in material breach of its obligations hereunder at
the time of such termination, as liquidated damages and not as a penalty or
forfeiture, an amount equal to the lesser of (m) $839,200 (the "Liquidated
Damages Amount") and (n) the sum of (1) the maximum amount that can be paid to
AIP without causing AIP to fail to meet the requirements of Sections 856(c)(2)
and (3) of the Code determined as if the payment of such amount did not
constitute income described in Sections 856(c)(2)(A)-(H) and 856(c)(3)(A)-(I)
of the Code ("Qualifying Income"), as determined by AIP's certified public
accountants, plus (2) an amount equal to the Liquidated Damages Amount less the
amount payable under clause (1) above in the event AIP receives a letter from
AIP's counsel indicating that AIP has received a ruling from the IRS to the
effect that Liquidated Damages Amount payments constitute Qualifying Income. In
addition to the Liquidated Damages Amount, AIP shall be entitled to receive
from RELP (or its successor in interest) all documented out-of-pocket costs and
expenses, up to a maximum of $419,600 in connection with this Agreement and the
transactions contemplated hereby (the "AIP Expenses") incurred by AIP. The
payments to which AIP is entitled under this Section 9.5(a) shall be its sole
remedy with respect to the termination of the Agreement under the circumstances
contemplated in this Section 9.5(a).

         (b)     If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.3(c) not
being satisfied), RELP shall, provided that AIP was not in material breach of
its obligations hereunder at the time of such termination, pay AIP for the AIP
Expenses, up to a maximum of $419,600, although it shall not be required to pay
the Liquidated Damages Amount, which payment of the AIP Expenses shall be AIP's
sole remedy for termination of the Agreement in such circumstances.





                                       30
<PAGE>   31
         (c)     If an election to terminate this Agreement is made pursuant to
(i) Section 9.2(i) (except as a result of a default or breach hereunder by
RELP) or Section 9.2(iii), and an AIP Acquisition Proposal relating to AIP
shall have been made and, within one year from the date of such termination,
AIP consummates an AIP Acquisition Proposal or enters into an agreement to
consummate an AIP Acquisition Proposal which is subsequently consummated, or
(ii) Section 9.4(i), AIP shall pay to RELP, provided that RELP was not in
material breach of its obligations hereunder at the time of such termination,
as liquidated damages and not as a penalty or forfeiture, an amount equal to
the Liquidated Damages Amount. In addition to the Liquidated Damages Amount,
RELP shall be entitled to receive from AIP (or its successor in interest) all
documented out-of-pocket costs and expenses, up to a maximum of $419,600, in
connection with this Agreement and the transactions contemplated hereby (the
"RELP Expenses" and, together with the AIP Expenses, the "Expenses")  incurred
by RELP. The payments to which RELP is entitled under this Section 9.5(c) shall
be its sole remedy with respect to the termination of the Agreement under the
circumstances contemplated in this Section 9.5(c)

         (d)     If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.2(c) not
being satisfied), AIP shall, provided that RELP was not in material breach of
its obligations hereunder at the time of such termination, pay RELP for the
RELP Expenses, up to a maximum of $419,600, although it shall not be required
to pay the Liquidated Damages Amount, which payment of the RELP Expenses shall
be RELP's sole remedy for termination of the Agreement in such circumstances.

         (e)     If this Agreement is terminated pursuant to Section 9.3(iv),
Section 9.3(v), Section 9.4(iv), or Section 9.4(v), the non-terminating party
shall, provided that the terminating party was not in material breach of its
obligations hereunder at the time of such termination, pay the terminating
party all Expenses, up to a maximum of $419,600, incurred by it and the
non-terminating party shall remain liable to the terminating party for its
breach.

         (f)      If either party terminates this Agreement during the Due
Diligence Period described in Section 9.2 above other than for a due diligence
related reason, the non-terminating party shall be entitled to receive the
Liquidated Damages Amount and the Expenses as provided in this Article IX.

         (g)     RELP agrees to amend this Section 9.5 at the request of AIP in
order to (x) maximize the portion of the Liquidated Damages Amount that may be
distributed to AIP hereunder without causing AIP to fail to meet the
requirements of Sections 856(c)(2) and (3) of the Code or (y) improve AIP's
chances of securing a favorable ruling described in this Section 9.5, provided
that no such amendment may result in any additional cost or expense to such
other party.

         (h)     In the event of termination of this Agreement and the
abandonment of the Merger pursuant to this Article IX, all obligations of the
parties hereto shall terminate, except the obligations of the parties pursuant
to this Section 9.5 and Section 7.10 and except for the provisions of Section
10.3, 10.4, 10.5, 10.6, 10.7, 10.9, 10.10, 10.13, 10.14 and 10.16. In the event
AIP or RELP has received the Liquidated Damages Amount, such recipient shall
not assert or pursue in any manner, directly or indirectly, any claim or cause
of action against the other party hereto or any of its officers, Trust
Managers, or  General Partners, as applicable, based in whole or part upon its
or their receipt,





                                       31
<PAGE>   32
consideration, recommendation or approval of an Acquisition Proposal or the
exercise by AIP of its right to termination under Section 9.4(i) or the
exercise by RELP of its right to termination under Section 9.3(i).
Notwithstanding the foregoing, in the event AIP or RELP is required to file
suit to seek all or a portion of such Liquidated Damages Amount, and it
ultimately succeeds, it shall be entitled to all expenses, including attorney's
fees and expenses, which it has incurred in enforcing its right hereunder.

         (i)     If either party willfully fails to perform its duties and
obligations under this Agreement, the non- breaching party is additionally
entitled to all remedies available to it at law or in equity and to recover its
expenses from the breaching party.

         9.6     Extension; Waiver.  At any time prior to the Effective Time,
any party hereto, by action taken by its Board of Trust Managers or General
Partner, as applicable, may, to the extent legally allowed, (i) extend the time
for the performance of any of the obligations or other acts of the other
parties hereto, (ii) waive any inaccuracies in the representations and
warranties made to such party contained herein or in any document delivered
pursuant hereto and (iii) waive compliance with any of the agreements or
conditions for the benefit of such party contained herein. Any agreement on the
part of a party hereto to any such extension or waiver shall be valid only if
set forth in an instrument in writing signed on behalf of such party.

                         ARTICLE X.  GENERAL PROVISIONS

         10.1.   Nonsurvival of Representations, Warranties and Agreements.
All representations, warranties and agreements in this Agreement or in any
instrument delivered pursuant to this Agreement shall not survive the Merger;
provided, however, that the agreements contained in Article IV, the last
sentence of Section 7.4 and Sections 7.10, 7.11, 7.12, 7.13, 7.14, 7.15 and
7.16 and this Article X shall survive the Merger.

         10.2.    Notices.  Any notice required to be given hereunder shall be
in writing and shall be sent by facsimile transmission (confirmed by any of the
methods that follow), courier service (with proof of service), hand delivery or
certified or registered mail (return receipt requested and first-class postage
prepaid) and addressed as follows:

         If to AIP:
         American Industrial Properties REIT
         6220 N. Beltline Road, Suite 205
         Irving, Texas 75063
         Attention: Charles W. Wolcott, President
         Telecopy: (972) 550-6037

         If to RELP:
         USAA Real Estate Company
         8000 I-H 10 West, Suite 600
         San Antonio, Texas 78230
         Attention: Patrick Duncan, Senior Vice-President
         Telecopy: (210) 498-6214





                                       32
<PAGE>   33
or to such other address as any party shall specify by written notice so given,
and such notice shall be deemed to have been delivered as of the date so
delivered.

         10.3.   Assignment; Binding Effect; Benefit.  Neither this Agreement
nor any of the rights, interests or obligations hereunder shall be assigned by
any of the parties hereto (whether by operation of law or otherwise) without
the prior written consent of the other parties. Subject to the preceding
sentence, this Agreement shall be binding upon and shall inure to the benefit
of the parties hereto and their respective successors and assigns.
Notwithstanding anything contained in this Agreement to the contrary, except as
provided in the following sentence, nothing in this Agreement, expressed or
implied, is intended to confer on any person other than the parties hereto or
their respective heirs, successors, executors, administrators and assigns any
rights, remedies, obligations or liabilities under or by reason of this
Agreement. The provisions of Article IV and Sections 7.11, 7.12, 7.13, 7.14 and
7.15 (collectively, the "Third Party Provisions") shall benefit the persons
identified therein, but the aggregate liability of AIP with respect thereto
shall not exceed the amount specified in Article IX.

         10.4.   Entire Agreement.  This Agreement, the Exhibits, the RELP
Disclosure Letter, the AIP Disclosure Letter, the RELP Ancillary Agreements,
the AIP Ancillary Agreements and any documents delivered by the parties in
connection herewith constitute the entire agreement among the parties with
respect to the subject matter hereof and supersede all prior agreements and
understandings among the parties with respect thereto. No addition to or
modification of any provision of this Agreement shall be binding upon any party
hereto unless made in writing and signed by all parties hereto.

         10.5.   Confidentiality.  (a)  As used herein, "Confidential Material"
means, with respect to either party hereto (the "Providing Party"), all
information (written or oral) furnished (whether before or after the date
hereof) by the Providing Party and its directors, officers, employees,
affiliates or representatives of advisors, including counsel, lenders and
financial advisors (collectively, the "Providing Party Representatives") to the
other party hereto (the "Receiving Party") or such Receiving Party's directors,
officers, employees, affiliates or representatives of advisors, including
counsel, lenders and financial advisors or the Receiving Party's potential
sources of financing for the transactions contemplated by this Agreement
(collectively "the Receiving Party Representatives") and all analyses,
compilations, forecasts and other studies or other documents prepared by the
Providing Party or the Providing Party Representatives in connection with its
or their review of the transactions contemplated by this Agreement which
contain or reflect such information. The term "Confidential Material" does not
include, however, information which (i) at the time of disclosure or thereafter
is generally available to and known by the public other than as a result of a
disclosure directly or indirectly by the Receiving Party or the Receiving Party
Representatives in violation of this Agreement, (ii) at the time of disclosure
was available on a nonconfidential basis from a source other than the Providing
Party or the Providing Party Representatives, providing that such source is not
and was not bound by a confidentiality agreement with the Providing Party,
(iii) was known by the Receiving Party prior to receiving the Confidential
Material from the Providing Party or has been independently acquired or
developed by the Receiving Party without violating any of its obligations under
this Agreement, or (iv) is contained in any RELP Reports or AIP Reports or
Proxy Statement/Prospectus.





                                       33
<PAGE>   34
         (b)     Subject to paragraph (c) below or except as required by law,
the Confidential Material will be kept confidential and will not, without the
prior written consent of the Providing Party, be disclosed by the Receiving
Party or its Representatives, in whole or in part and will not be used by the
Receiving Party or its Representatives, directly or indirectly, for any purpose
other than in connection with this Agreement, the Merger or the evaluating,
negotiating or advising with respect to a transaction contemplated herein.
Moreover, each Receiving Party agrees to transmit Confidential Material to its
Representatives only if and to the extent that such Representatives need to
know the Confidential Material for purposes of such transaction and are
informed by such Receiving Party of the confidential nature of the Confidential
Material and of the terms of this Section.

         (c)     In the event that either Receiving Party, its Representatives
or anyone to whom such Receiving Party or its Representatives supply the
Confidential Material, are requested or required (by oral questions,
interrogatories, requests for information or documents, subpoena, civil
investigative demand, any informal or formal investigation by any government or
governmental agency or authority or otherwise in connection with legal
processes) to disclose any Confidential Material, such Receiving Party agrees
(i) to immediately notify the Providing Party of the existence, terms and
circumstances surrounding such a request, (ii) to consult with the Providing
Party on the advisability of taking legally available steps to resist or narrow
such request and (iii) if disclosure of such information is required, to
furnish only that portion of the Confidential Material which, in the opinion of
such Receiving Party's counsel, such Receiving Party is legally compelled to
disclose and to cooperate with any action by the Providing Party to obtain an
appropriate protective order or otherwise reliable assurances that confidential
treatment will be accorded the Confidential Material (it being agreed that the
Providing Party shall reimburse the Receiving Party for all reasonable
out-of-pocket expenses incurred by the Receiving Party in connection with such
cooperation).

         (d)     In the event of the termination of this Agreement in
accordance with its terms, promptly upon request from either Providing Party,
the Receiving Party shall, except to the extent prevented by law, redeliver to
the Providing Party or destroy all tangible Confidential Material and will not
retain any copies, extracts or other reproductions thereof in whole or in part.
Any such destruction shall be certified in writing to the Providing Party by an
authorized officer of the Receiving Party supervising the same. Notwithstanding
the foregoing, each Receiving Party and one Representative designated by each
Receiving Party shall be permitted to retain one permanent file copy of each
document constituting Confidential Material.

         (e)     Each party hereto further agrees that if this Agreement is
terminated in accordance with its terms, until one year from the date of
termination, (1) it will not offer to hire or hire any person currently or
formerly employed by the other party with whom such party has had contact prior
hereto other than persons whose employment shall have been terminated by such
other party prior to the date of such offer to hire or hiring and (2) neither
it nor its affiliates shall directly or indirectly, (a) (w) solicit, seek or
offer to effect or effect, (x) negotiate with or provide any information to the
Board of Trust Managers or General Partner, as applicable, of the other party,
or officer of the other party or any shareholder or partner, as applicable, of
the other party with respect to, (y) make any statement or proposal, whether
written or oral, either alone or in concert with others, to the Board of Trust
Managers or Board of Directors of the General Partner of the other party, any
director, Trust Manager or officer of the other party or any shareholder or
partner of the other party or any other person with respect to, or (z) make any
public announcement (except as required by law in respect





                                       34
<PAGE>   35
of actions permitted hereby) or proposal or offer whatsoever (including, but
not limited to, any "solicitation"of "proxies"as such terms are defined or used
in Regulation 14A of the Exchange Act) with respect to, (i) any form of
business combination or similar or other extraordinary transaction involving
the other party or any affiliate thereof, including, without limitation, a
merger, tender or exchange offer or liquidation of the other party's assets,
(ii) any form of restructuring, recapitalization or similar transaction with
respect to the other party or any affiliate thereto, (iii) any purchase of any
securities or assets, or rights or options to acquire any securities or assets
(through purchase, exchange, conversion or otherwise), of the other party or
any affiliate thereof, (iv) any proposal to seek representation on the Board of
Trust Managers or the Board of Directors of the General Partner, as
applicable, or otherwise to seek to control or influence the management, Board
of Trust Managers or the Board of Directors of the General Partner, as
applicable, or policies of the other party or any affiliate thereof, (v) any
request or proposal to waive, terminate or amend the provisions of this Section
10.5 or (vi) any proposal or other statement inconsistent with the terms of
this Section 10.5 or (b) instigate, encourage, join, act in concert with or
assist (including, but not limited to, providing or assisting in any way in the
obtaining of financing for, or acting as a joint or co-bidder for the other
party with) any third party to do any of the foregoing, unless and until such
party has received the prior written invitation or approval of a majority of
the Board of Trust Managers or the General Partner, as applicable, to do any of
the foregoing; provided that without such invitation or approval, either party
may at any time, on a confidential non-public basis, submit to the Chief
Executive Officer of AIP or the General Partner, as applicable, a proposal to
(a) amend any of the provisions of this Section 10.5(e) or (b) effect a
business combination or other extraordinary transaction with the other party
providing for the acquisition of all or substantially all of the assets or the
securities of the other party, including, without limitation, a merger, tender
offer or exchange offer. Each party hereto agrees that it will not agree with
any third party to waive its rights under this Section 10.5.

         10.6.   Amendment.  This Agreement may be amended by the parties
hereto, by action taken by the Board of Trust Managers or the Board of
Directors of the General Partner, as applicable, at any time before or after
approval of this Agreement or any other matter presented in connection with the
Merger by the shareholders of AIP and partners of RELP, but after any such
approval, no amendment shall be made which by law requires the further approval
of shareholders or partners, as applicable, without obtaining such further
approval. This Agreement may not be amended except by an instrument in writing
signed on behalf of each of the parties hereto.

         10.7.   Governing Law.  This Agreement shall be governed by and
construed in accordance with the laws of the State of Texas without regard to
its rules of conflict of laws. Each of AIP and RELP hereby irrevocably and
unconditionally consents to submit to the exclusive jurisdiction of the courts
of the State of Texas and of the United States District Court, Northern
District of Texas (the "Texas Courts") for any litigation arising out of or
relating to this Agreement and the transactions contemplated hereby (and agrees
not to commence any litigation relating thereto except in such courts), waives
any objection to the laying of venue of any such litigation in the Texas Courts
and agrees not to plead or claim in any Texas Court that such litigation
brought therein has been brought in an inconvenient forum.





                                       35
<PAGE>   36
         10.8.   Counterparts.  This Agreement may be executed by the parties
hereto in separate counterparts, each of which when so executed and delivered
shall be an original, but all such counterparts shall together constitute one
and the same instrument. Each counterpart may consist of a number of copies
hereof each signed by less than all, but together signed by all of the parties
hereto.

         10.9.   Headings.  Heading of the Articles and Sections of this
Agreement are for the convenience of the parties only and shall be given no
substantive or interpretive effect whatsoever.

         10.10.  Interpretation.  In this Agreement, unless the context
otherwise requires, words describing the singular number shall include the
plural and vice versa, and words denoting any gender shall include all genders
and words denoting natural persons shall include corporations and partnerships
and vice versa.

         10.11.  Waivers.  Except as provided in this Agreement, no action
taken pursuant to this Agreement, including, without limitation, any
investigation by or on behalf of any party, shall be deemed to constitute a
waiver by the party taking such action of compliance with any representations,
warranties, covenants or agreements contained in this Agreement. The waiver by
any party hereto of a breach of any provision hereunder shall not operate or be
construed as a waiver of any prior or subsequent breach of the same or any
other provision hereunder.

         10.12.  Incorporation.  The RELP Disclosure Letter and the AIP
Disclosure Letter and all Exhibits and Schedules attached hereto and thereto
and referred to herein and therein are hereby incorporated herein and made a
part hereof for all purposes as if fully set forth herein.

         10.13.  Severability.    If any provision of this Agreement is held to
be illegal, invalid or unenforceable under any current or future law, and if
the rights or obligations of the parties under this Agreement would not be
materially and adversely affected thereby, such provision shall be fully
separable, and this Agreement shall be construed and enforced as if such
illegal, invalid or unenforceable provision had never comprised a part thereof,
and the remaining provisions of this Agreement shall remain in full force and
effect and shall not be affected by the illegal, invalid or unenforceable
provision or by its severance therefrom.  In lieu of such illegal, invalid or
unenforceable provision, there shall be added automatically as a part of this
Agreement, a legal, valid and enforceable provision as similar in terms to such
illegal, invalid or unenforceable provision as may be possible, and the parties
hereto request the court or any arbitrator to whom disputes relating to this
Agreement are submitted to reform the otherwise illegal, invalid or
unenforceable provision in accordance with this Section 10.13.

         10.14.  Enforcement of Agreement.  The parties hereto agree that
irreparable damage would occur in the event that any of the provisions of this
Agreement was not performed in accordance with its specific terms or was
otherwise breached. It is accordingly agreed that the parties shall be entitled
to an injunction or injunctions to prevent breaches of this Agreement and to
enforce specifically the terms and provisions hereof in any Texas Court, this
being in addition to any other remedy to which they are entitled at law or in
equity.





                                       36
<PAGE>   37
         10.15.  Subsidiaries.  As used in this Agreement, the word
"Subsidiary" when used with respect to any party means any corporation,
partnership, joint venture, business trust or other entity, of which such party
directly or indirectly owns or controls at least a majority of the securities
or other interests having by their terms ordinary voting power to elect a
majority of the board of directors or others performing similar functions with
respect to such corporation or other organization.

         10.16.  Non-Recourse.  Neither the officers, Trust Managers nor
shareholders of AIP shall be personally bound or have any personal liability
hereunder. RELP shall look solely to the assets of AIP for satisfaction of any
liability of AIP with respect to this Agreement and the Ancillary Agreements to
which it is a party. RELP will not seek recourse or commence any action against
any of the shareholders of AIP or any of their personal assets, and will not
commence any action for money judgments against any of the Trust Managers or
officers of AIP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of AIP hereunder or thereunder. The
partners of RELP shall not be personally bound or have any personal liability
hereunder. AIP shall look solely to the assets of RELP for satisfaction of any
liability of RELP with respect to this Agreement and the Ancillary Agreements
to which it is a party. AIP will not seek recourse or commence any action
against any of the partners of RELP or any of their personal assets, and will
not commence any action for money judgments against any of the directors or
officers of RELP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of RELP hereunder or thereunder.

         IN WITNESS WHEREOF, the parties have executed this Agreement and
caused the same to be duly delivered on their behalf on the day and year first
written above.

                                             AMERICAN INDUSTRIAL PROPERTIES REIT


                                             /s/ Charles W. Wolcott           
                                             -----------------------------------
                                             Charles W. Wolcott, President and
                                             Chief Executive Officer          


                                             USAA INCOME PROPERTIES III LIMITED 
                                             PARTNERSHIP

                                             By: USAA Properties III, Inc., Its 
                                                 General Partner



                                                 /s/ T. Patrick Duncan        
                                                 -------------------------------
                                                 T. Patrick Duncan
                                                 Senior Vice President - 
                                                 Operations





                                       37

<PAGE>   1
                                                                     EXHIBIT 2.4

                              AMENDED AND RESTATED
                          AGREEMENT AND PLAN OF MERGER

         THIS AMENDED AND RESTATED AGREEMENT AND PLAN OF MERGER (this
"Agreement"), dated as of June 30, 1997, is entered into by and between
American Industrial Properties REIT, a Texas real estate investment trust
("AIP") , and USAA Income Properties IV Limited Partnership, a Delaware limited
partnership ("RELP").  USAA Real Estate Company, a Delaware corporation
("Realco"), is a party to this Agreement solely for the purpose of binding
itself to the provisions of Section 7.10 hereunder.

                                    RECITALS

         A.      The Board of Trust Managers of AIP (the "Board of Trust
Managers") and the general partner of RELP have each determined that a business
combination between AIP and RELP is in the best interests of their shareholders
and partners, respectively, and presents an opportunity for their respective
businesses to achieve strategic and financial benefits, and accordingly have
agreed to effect a merger subject to the terms and conditions set forth herein.

         B.      AIP and RELP desire to make certain representations,
warranties and agreements in connection with the merger.

         NOW, THEREFORE, in consideration of the foregoing, and of the
representations, warranties, covenants and agreements contained herein, AIP and
RELP hereby agree as follows:

                             ARTICLE I.  THE MERGER

         1.1.    The Merger. Subject to the terms and conditions of this
Agreement, at the Effective Time (as defined in Section 1.3), RELP shall be
merged with and into AIP in accordance with this Agreement and the Plan of
Merger (the "Plan of Merger") in substantially the form attached hereto as
Exhibit A, with such completions, additions and substitutions conforming to the
terms of this Agreement as the parties shall approve, such approval to be
conclusively evidenced by their causing the Plan of Merger containing such
completions, additions or substitutions to be filed in accordance with
applicable laws; and the separate existence of RELP shall thereupon cease (the
"Merger"). AIP shall be the surviving entity in the Merger (sometimes
hereinafter referred to as the "Survivor").  The Merger shall have the effects
specified in Section 23.60  of the Texas Real Estate Investment Trust Act, as
amended (the "Texas REIT Act") and Section 17-211 of the Delaware Revised
Uniform Limited Partnership Act (the "LP Act").

         1.2.    The Closing. Subject to the terms and conditions of this
Agreement, the closing of the Merger (the "Closing") shall take place at the
offices of Liddell, Sapp, Zivley, Hill & LaBoon, L.L.P. ("Liddell, Sapp"),
located at 2200 Ross Avenue, Suite 900, Dallas, Texas at 10:00 a.m., local
time, within five business days after receipt of approval of the Merger by
AIP's shareholders and RELP's partners, or at such other time, date or place as
AIP and RELP may agree. The date on which the Closing occurs is hereinafter
referred to as the "Closing Date."

<PAGE>   2
         1.3.    Effective Time. If all the conditions to the Merger set forth
in Article VIII shall have been fulfilled or waived (and this Agreement shall
not have been terminated as provided in Article IX), AIP and RELP shall cause
Articles of Merger satisfying the requirements of the Texas REIT Act and
Articles of Merger satisfying the requirements of the LP Act to be properly
executed, verified and delivered for filing in accordance with the LP Act and
the Texas REIT Act on the Closing Date. The Merger shall become effective for
accounting and all other purposes to the fullest extent permitted by law as of
the close of business on December 31, 1997 (the "Effective Time") or such other
date as may be agreed to by the parties. For state law purposes, the Merger
shall become effective upon the issuance of a certificate of merger by the
Secretary of State of the State of Delaware in accordance with the LP Act or at
such later time which AIP and RELP shall have agreed upon and designated in
such filings in accordance with applicable law.

                       ARTICLE II.  DECLARATION OF TRUST
                           AND BYLAWS OF THE SURVIVOR

         2.1.    Declaration of Trust.  The Declaration of Trust of AIP  in
effect immediately prior to the Effective Time shall be the Declaration of
Trust of the Survivor until duly amended in accordance with applicable law.

         2.2.    Bylaws.  The Bylaws of AIP in effect immediately prior to the
Effective Time shall be the Bylaws of the Survivor until duly amended in
accordance with applicable law.

                ARTICLE III.  TRUST MANAGERS AND OFFICERS OF AIP

         3.1.    Trust Managers.  The Trust Managers of AIP immediately prior
to the Effective Time shall be the Trust Managers of AIP as of the Effective
Time.

         3.2.     Officers.  The officers of AIP immediately prior to the
Effective Time shall be the officers of AIP as of the Effective Time.

                    ARTICLE IV.  RELP PARTNERSHIP  INTERESTS

         4.1.    Conversion of the RELP Partnership Interest.  (a)   At the
Effective Time, each Common Share of Beneficial Interest of AIP outstanding
immediately prior to the Effective Time shall remain outstanding and shall
represent one Common Share of Beneficial Interest of AIP.

         (b)     At the Effective Time, the general and limited partnership
interests of RELP  (each a  "RELP Interest"), issued and outstanding
immediately prior to the Effective Time shall, by virtue of the Merger and
without any action on the part of holder thereof, be converted into the right
to receive Common Shares of Beneficial Interest, $0.10 par value per share (the
"AIP Common Shares"), of AIP.  The aggregate number of AIP Common Shares to be
issued to the RELP partners in connection with the Merger shall be equal to
$12,018,387 (the "Purchase Price") divided by the Share Price (the "Total
Shares").  If, during the period from the date hereof to and including the
Closing Date, (i) the RELP pays any mortgage indebtedness existing on the date
hereof or (ii) the outstanding AIP Common Shares shall have been changed to a
different number of shares by reason of any share dividend, subdivision,
reclassification, recapitalization, share split, reverse share split,



                                      2
<PAGE>   3
combination, exchange of shares or the like, the Purchase Price shall be
appropriately adjusted.  The term "Share Price" shall mean $2.625.  The number
of AIP Common Shares to be received by a partner shall be equal to the Total
Shares multiplied by such partner's percentage interest in RELP plus each
limited partner's pro rata portion of the general partnership interest of the
RELP's general partner.

         (c)     As a result of the Merger and without any action on the part
of the holder thereof, at the Effective Time,  all RELP Interests  shall cease
to be outstanding and shall be canceled and retired, and each holder of a RELP
Interest shall thereafter cease to have any rights with respect to such RELP
Interest, except the right to receive, without interest, the AIP Common Shares
and cash for fractional shares of AIP Common Shares in accordance with Sections
4.1(b) and 4.2(e).

         4.2.    Exchange of RELP Interests.  (a)  As of the Effective Time,
AIP shall deposit, or shall cause to be deposited, with an exchange agent
selected by AIP, which shall be AIP's Transfer Agent or such other party
reasonably satisfactory to RELP (the "Exchange Agent"), for the benefit of the
holders of RELP Interests, for exchange in accordance with this Article IV,
certificates representing the Total Shares and the cash in lieu of fractional
shares (such cash and certificates for the Total Shares together with any
dividends or distributions with respect thereto, being hereinafter referred to
as the "Exchange Fund") to be issued pursuant to Section 4.1 and paid pursuant
to this Section 4.2 in exchange for outstanding RELP Interests.

         (b)     Promptly after the Effective Time, AIP shall cause the
Exchange Agent to mail to each holder of record of a RELP Interest (x) a
certificate representing the number of whole shares of AIP Common Shares and
(y) a check representing the amount of cash in lieu of fractional shares, if
any, and unpaid dividends and distributions, if any, which such holder has the
right to receive in respect of the RELP Interest surrendered pursuant to the
provisions of this Article IV, after giving effect to any required withholding
tax.  No interest will be paid or accrued on the cash in lieu of fractional
shares and unpaid dividends and distributions, if any, payable to holders of
RELP Interests.  In the event of a transfer of ownership of RELP Interests
which is not registered in the transfer records of RELP, a certificate
representing the proper number of AIP Common Shares, together with a check for
the cash to be paid in lieu of fractional shares, may be issued to such a
transferee if such holder presents to the Exchange Agent, all documents
required to evidence and effect such transfer and to evidence that any
applicable transfer taxes have been paid.

         (c)     At and after the Effective Time, there shall be no transfers
on the transfer books of RELP of RELP Interests which were outstanding
immediately prior to the Effective Time.

         (d)     No fractional AIP Common Shares shall be issued pursuant
hereto. In lieu of the issuance of any fractional AIP Common Shares pursuant to
Section 4.1(b), cash adjustments will be paid to holders in respect of any
fractional AIP Common Shares that would otherwise be issuable, and the amount
of such cash adjustment shall be equal to such fractional proportion of the
Share Price.





                                       3
<PAGE>   4
         (e)     Any portion of the Exchange Fund (including the proceeds of
any investments thereof and any AIP Common Shares) that remains unclaimed by
the former partners of RELP one year after the Effective Time shall be
delivered to AIP. Any former partners of RELP who have not theretofore complied
with this Article IV shall thereafter look only to AIP for delivery of their
AIP Common Shares, and payment of cash in lieu of fractional shares and unpaid
dividends and distributions on the AIP Common Shares deliverable in respect of
each RELP Interest such partners hold as determined pursuant to this Agreement,
in each case, without any interest thereon.

         (f)     None of AIP, RELP, the Exchange Agent or any other person
shall be liable to any former holder of RELP Interests for any amount properly
delivered to a public official pursuant to applicable abandoned property,
escheat or similar laws.


               ARTICLE V.  REPRESENTATIONS AND WARRANTIES OF RELP

         RELP represents and warrants to AIP as set forth below. As
contemplated below, a "RELP Disclosure Letter" will be delivered to AIP on or
before September 20, 1997.  The RELP Disclosure Letter shall provide the
information or exceptions described below and shall list all of the assets of
the RELP that will not be transferred in connection with the Merger. The RELP
Disclosure Letter shall be amended prior to Closing to cause such
representations and warranties to be materially true and correct on the Closing
Date, but RELP shall remain liable for any material breach of such
representations and warranties reflected in such amendment only as provided in
Section 9.5(d), below.

         5.1.    Existence; Good Standing; Authority; Compliance with Law.  (a)
RELP is a limited partnership,  duly formed, validly existing and in good
standing under the laws of the State of Delaware.  To its actual knowledge,
RELP is duly licensed or qualified to do business as a foreign limited
partnership and is in good standing under the laws of any other state of the
United States in which the character of the properties owned or leased by it
therein or in which the transaction of its business makes such qualification
necessary, except where the failure to be so qualified would not have a
material adverse effect on the business, results of operations or financial
condition of RELP (a "RELP Material Adverse Effect"). RELP has all requisite
power and authority to own, operate, lease and encumber its properties and
carry on its business as now conducted.

         (b)      To the RELP's actual knowledge, it is not in violation of any
order of any court, governmental authority or arbitration board or tribunal, or
any law, ordinance, governmental rule or regulation to which RELP or any of its
properties or assets is subject, where such violation would have a RELP
Material Adverse Effect. RELP has obtained all licenses, permits and other
authorizations and has taken all actions required by applicable law or
governmental regulations in connection with its business as now conducted,
where the failure to obtain any such item or to take any such action would have
a RELP Material Adverse Effect. A copy of RELP's Agreement of Limited
Partnership and Certificate of Limited Partnership (collectively, the "RELP
Organizational Documents") have been delivered or made available to AIP and its
counsel and such documents will be listed in the RELP Disclosure Letter and
were or will be true and correct when delivered or made available.





                                       4
<PAGE>   5
         5.2.    Authorization, Validity and Effect of Agreements.  RELP has
the requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions contemplated by this
Agreement (the "RELP Ancillary Agreements"). Subject only to the approval of
this Agreement and the transactions contemplated hereby in accordance with the
Agreement of Limited Partnership of the RELP, the consummation by RELP of this
Agreement, the RELP Ancillary Agreements and the transactions contemplated
hereby have been duly authorized by all requisite action on the part of RELP.
In reliance upon the legal opinion described in Section 8.2(e), RELP believes
this Agreement constitutes, and the RELP Ancillary Agreements (when executed
and delivered pursuant hereto for value received) will constitute, the valid
and legally binding obligations of RELP, enforceable against RELP in accordance
with their respective terms, subject to applicable bankruptcy, insolvency,
moratorium or other similar laws relating to creditors' rights and general
principles of equity (collectively, "Equitable Remedies").

         5.3.    Future Issuances.  To RELP's actual knowledge, there are not
at the date of this Agreement any existing options, warrants, calls,
subscriptions, convertible securities, or other rights, agreements or
commitments which obligate RELP to issue, transfer or sell any RELP Interests.
After the Effective Time, AIP will have no obligation to issue, transfer or
sell any RELP Interest.

         5.4.    Other Interests.  Except as set forth in the RELP Disclosure
Letter, RELP does not own directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

         5.5.    No Violation.  To RELP's actual knowledge, neither the
execution and delivery by RELP of this Agreement nor the consummation by RELP
of the transactions contemplated hereby in accordance with the terms hereof,
will: (i) conflict with or result in a breach of any provisions of the
Agreement of Limited Partnership of RELP; (ii) except as contemplated by the
RELP Ancillary Agreements or as will be set forth in the RELP Disclosure
Letter, violate, or conflict with, or result in a breach of any provision of,
or constitute a default (or an event which, with notice or lapse of time or
both, would constitute a default) under, or result in the termination or in a
right of termination or cancellation of, or accelerate the performance required
by, or result in the creation of any lien, security interest, charge or
encumbrance upon any of the properties of RELP under, or result in being
declared void, voidable or without further binding effect, any of the terms,
conditions or provisions of any note, bond, mortgage, indenture, deed of trust
or any license, franchise, permit, lease, contract, agreement or other
instrument, commitment or obligation to which RELP is a party, or by which RELP
or any of its  properties is bound or affected, except for any of the foregoing
matters which, individually or in the aggregate, would not have a RELP Material
Adverse Effect; or (iii) other than the filings provided for in Article I, any
filings required under the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), the Securities Act or applicable state securities and "Blue
Sky" laws (collectively, the "Regulatory Filings"), require any consent,
approval or authorization of, or declaration, filing or registration with, any
domestic governmental or regulatory authority, except where the failure to
obtain any such consent, approval or authorization of, or declaration, filing
or registration with, any governmental or regulatory authority would not have
an RELP Material Adverse Effect.





                                       5
<PAGE>   6
         5.6.    SEC Documents.  (a) RELP has made available or will make
available to AIP prior to September 30, 1997, each registration statement,
report, proxy statement or information statement and all exhibits thereto
prepared by it or relating to its properties (including registration statements
covering mortgage pass-through certificates) since January 1, 1994, each in the
form (including exhibits and any amendments thereto) filed with the SEC
(collectively, the "RELP Reports"). The RELP Reports, which were or will be
filed with the SEC in a timely manner, constitute all forms, reports and
documents required to be filed by RELP under the Securities Act of 1933, as
amended (the "Securities Act"), the Exchange Act and the rules and regulations
promulgated thereunder (collectively the "Securities Laws") for the periods
stated above.

         (b)     To the RELP's actual knowledge, as of their respective dates,
the RELP Reports (i) complied as to form in all material respects with the
applicable requirements of the Securities Laws and (ii) did not contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements made therein, in the
light of the circumstances under which they were made, not misleading. To the
RELP's actual knowledge, each of the balance sheets of RELP included in or
incorporated by reference into the RELP Reports (including the related notes
and schedules) fairly presents the financial position of RELP as of its date
and each of the consolidated statements of income, retained earnings and cash
flows of RELP included in or incorporated by reference into the RELP Reports
(including any related notes and schedules) fairly presents the results of
operations, retained earnings and cash flows, as the case may be, of RELP for
the periods set forth therein (subject, in the case of unaudited statements, to
normal year-end audit adjustments which would not be material in amount or
effect), in each case in accordance with generally accepted accounting
principles consistently applied during the periods involved, except as may be
noted therein and except, in the case of the unaudited statements, as permitted
by the Securities Laws.


         (c)     Except as and to the extent set forth on the balance sheet of
RELP at March 31, 1997, including all notes thereto, or as set forth in the
RELP Reports, RELP has no material liabilities or obligations of any nature
(whether accrued, absolute, contingent or otherwise) that would be required to
be reflected on, or reserved against in, a balance sheet of RELP or in the
notes thereto, prepared in accordance with generally accepted accounting
principles consistently applied, except liabilities arising in the ordinary
course of business since such date which would not have a RELP Material Adverse
Effect.

         5.7.    Litigation.  To the RELP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which RELP is a party or by which any of its
properties or assets are bound or to which USAA Properties IV, Inc. (the
"General Partner")  or the General Partner's,  directors, officers, or
affiliates is a party or by which any of their properties or assets are bound,
and (ii) except as will be set forth in the RELP Disclosure Letter, no actions,
suits or proceedings pending against RELP or against the General Partner or the
General Partner's directors, officers or affiliates or, to the knowledge of the
General Partner, threatened against RELP or against the General Partner or the
General Partner's  directors, officers  or affiliates, at law or in equity, or
before or by any federal or state commission, board, bureau, agency or
instrumentality, that in the case of clauses (i) or (ii) above are reasonably
likely, individually or in the aggregate, to have a RELP Material Adverse
Effect.





                                       6
<PAGE>   7
         5.8.    Absence of Certain Changes.  Except as disclosed in the RELP
Reports filed prior to the date hereof, since March 31, 1997, (i) RELP
conducted its business only in the ordinary course of such business (which for
purposes of this section only, shall include all acquisitions of real estate
properties and financing arrangements made in connection therewith or otherwise
will be set forth in the RELP Disclosure Letter); (ii) there has not been any
RELP Material Adverse Effect; (iii) there has not been any distribution,
setting aside or payment of any distribution with respect to any RELP Interest,
and (iv) there has not been any material change in RELP's accounting
principles, practices or methods.

         5.9.    Taxes.  (a)  Except as may be set forth in the RELP Disclosure
Letter, RELP (i) has timely filed all federal, state and foreign tax returns
including, without limitation, information returns and reports required to be
filed by it for tax periods ended prior to the date of this Agreement or
requests for extensions have been timely filed and any such request has been
granted and has not expired and all such returns are accurate and complete in
all material respects, (ii) has paid or accrued all taxes shown to be due and
payable on such returns or which have become due and payable pursuant to any
assessment, deficiency notice, 30-day letter or other notice received by it and
(iii) has properly accrued all taxes for such periods and periods subsequent to
the periods covered by such returns. RELP has not received notice that the
federal, state and local income and franchise tax returns of RELP has been or
will be examined by any taxing authority. RELP has not executed or filed with
the Internal Revenue Service (the "IRS") or any other taxing authority any
agreement now in effect extending the period for assessment or collection of
any income or other taxes.

         (b)     Except as may be set forth in the RELP Disclosure Letter, RELP
is not  a party to any pending action or proceeding by any governmental
authority for assessment or collection of taxes, and no claim for assessment or
collection of taxes has been asserted against it. True, correct and complete
copies of all federal, state and local income or franchise tax returns filed by
RELP since January 1, 1991 and all communications relating thereto have been
delivered to AIP or made available to representatives of AIP or will be so
delivered or made available prior to September 30, 1997. RELP does not hold any
asset (i) the disposition of which could be subject to rules similar to Section
1374 of the Internal Revenue Code of 1986, as amended (the "Code") as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 5.9, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

         5.10.   Books and Records.  The books of account and other financial
records of RELP are in all material respects true, complete and correct, have
been maintained in accordance with good business practices, and are accurately
reflected in all material respects in the financial statements included in the
RELP Reports.

         5.11.   Properties.  (a)  RELP owns fee simple title to each of the
real properties reflected on the most recent balance sheet of RELP included in
the RELP Reports or as may be identified in the RELP Disclosure Letter (the
"RELP Properties"), which are all of the real estate properties owned by it,
free and clear of liens, mortgages or deeds of trust, claims against title,
charges which are liens or security interests ("Encumbrances") except as will
be noted in the RELP Disclosure Letter. To RELP's actual knowledge, the RELP
Properties are not subject to any rights of way, written agreements, laws,
ordinances and regulations affecting building use or occupancy, or reservations





                                       7
<PAGE>   8
of an interest in title (collectively, "Property Restrictions"), except for (i)
Encumbrances and Property Restrictions that will be set forth in the RELP
Disclosure Letter, (ii) Property Restrictions imposed or promulgated by law or
any governmental body or authority with respect to real property, including
zoning regulations, provided they do not materially adversely affect the
current use of the property, (iii) Encumbrances and Property Restrictions
disclosed on existing title reports or current surveys (in either case copies
of which title reports and surveys have been or will be delivered or made
available to AIP September 30, 1997), (iv) mechanics', carriers', workmen's,
repairmen's liens and other Encumbrances, Property Restrictions and other
limitations of any kind, if any, which have heretofore been bonded (and that
will be listed in the RELP Disclosure Letter) or which individually or in the
aggregate do not exceed $100,000, do not materially detract from the value of
or materially interfere with the present use of any of the RELP Properties
subject thereto or affected thereby, and do not otherwise materially impair
business operations conducted by RELP and which have arisen or been incurred
only in its construction activities or in the ordinary course of business.

         (b)     Valid policies of title insurance have been issued insuring
either (a) RELP's fee simple title to the RELP Properties or (b) first mortgage
liens thereon, subject only to the matters disclosed above and as may be set
forth in the RELP Disclosure Letter, and such policies are, at the date hereof,
in full force and effect and no claim has been made against any such policy. To
RELP's actual knowledge, except as will be set forth in the RELP Disclosure
Letter: (i) there is no certificate, permit or license from any governmental
authority having jurisdiction over any of the RELP Properties or any agreement,
easement or other right which is necessary to permit the lawful use and
operation of the buildings and improvements on any of the RELP Properties or
which is necessary to permit the lawful use and operation of all driveways,
roads and other means of egress and ingress to and from any of the RELP
Properties that has not been obtained and is not in full force and effect, or
of any pending threat of modification or cancellation of any of same; (ii) RELP
has not received written notice of any material violation of any federal, state
or municipal law, ordinance, order, regulation or requirement affecting any
portion of any of the RELP Properties issued by any governmental authority;
(iii) there are no structural defects relating to the RELP Properties and no
RELP Properties whose building systems are not in working order in any material
respect; and (iv) there is (A) no physical damage to any RELP Property in
excess of $100,000 for which there is no insurance in effect covering the cost
of the restoration, (B) no current renovation to any RELP Property the cost of
which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any RELP Property, the cost of which exceeds $100,000.

         (c)     Except as will be set forth in the RELP Disclosure Letter,
RELP has not received notice to the effect that and there are no (A)
condemnation or rezoning proceedings that are pending or threatened with
respect to any of the RELP Properties or (B) zoning, building or similar laws,
codes, ordinances, orders or regulations that are or will be violated by the
continued maintenance, operation or use of any buildings or other improvements
on any of the RELP Properties or by the continued maintenance, operation or use
of the parking areas. All work to be performed, payments to be made and actions
to be taken by RELP prior to the date hereof pursuant to any agreement entered
into with a governmental body or authority in connection with a site approval,
zoning





                                       8
<PAGE>   9
reclassification or other similar action relating to the RELP Properties (e.g.,
Local Improvement District, Road Improvement District, Environmental
Mitigation) has been performed, paid or taken, as the case may be, and RELP is
not aware of any planned or proposed work, payments or actions that may be
required after the date hereof pursuant to such agreements, except as will be
set forth in the RELP Disclosure Letter.

         5.12.   Environmental Matters.  To RELP's actual knowledge, RELP has
not  caused (i) the unlawful presence of any hazardous substances, hazardous
materials, toxic substances or waste materials (collectively, "Hazardous
Materials") on any of the RELP Properties, or (ii) any unlawful spills,
releases, discharges or disposal of Hazardous Materials to have occurred or be
presently occurring on or from the RELP Properties as a result of any
construction on or operation and use of such properties, which presence or
occurrence would, individually or in the aggregate, have a RELP Material
Adverse Effect; and in connection with the construction on or operation and use
of the RELP Properties, RELP has not failed to comply, in any material respect,
with any applicable local, state and federal environmental laws, regulations,
ordinances and administrative and judicial orders relating to the generation,
recycling, reuse, sale, storage, handling, transport and disposal of any
Hazardous Materials.

         5.13.   Labor Matters.  RELP is not a party to, or bound by, any
collective bargaining agreement, contract or other agreement or understanding
with a labor union or labor union organization. There is no unfair labor
practice or labor arbitration proceeding pending or, to the knowledge of the
General Partner, threatened against RELP relating to its business, except for
any such proceeding which would not have a RELP Material Adverse Effect. To the
knowledge of the General Partner, there are no organizational efforts with
respect to the formation of a collective bargaining unit presently being made
or threatened involving employees of RELP or any of its Subsidiaries.

         5.14.    No Brokers.  Except the fee that is to be paid to Houlihan
Lokey Howard & Zukin ("Houlihan")  by RELP as described in Section 5.15 below,
RELP has not entered into any contract, arrangement or understanding with any
person or firm which may result in the obligation of RELP or AIP to pay any
finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby. RELP is not aware of any claim for
payment of any finder's fees, brokerage or agent's commissions or other like
payments in connection with the negotiations leading to this Agreement or the
consummation of the transactions contemplated hereby.

         5.15.    Opinion of Financial Advisor.  RELP has retained Houlihan to
review the transaction contemplated by this Agreement and to issue an opinion
to the effect that, as of the date of such opinion, the Purchase Price is fair
to the holders of RELP Interests from a financial point of view.

         5.16.    Related Party Transactions.  Except as set forth in the RELP
Disclosure Letter, there are no arrangements, agreements or contracts entered
into by RELP with (i) any consultant, (ii) any person who is an officer,
director or affiliate of RELP or its General Partner, any relative of any of
the foregoing or any entity of which any of the foregoing is an affiliate, or
(iii) any person who acquired RELP Interests in a private placement.





                                       9
<PAGE>   10
         5.17.    Contracts and Commitments.  The RELP Disclosure Letter will
set forth (i) all unsecured notes or other obligations of RELP which
individually may result in total payments in excess of $100,000, (ii) all
notes, debentures, bonds and other evidence of indebtedness which are secured
or collateralized by mortgages, deeds of trust or other security interests in
the RELP Properties or personal property of RELP,  and (iii) each commitment
entered into by RELP which may result in total payments or liability in excess
of $100,000. Copies of the foregoing will be delivered or made available to AIP
prior to September 30, 1997, will be listed on the RELP Disclosure Letter and
will be materially true and correct when delivered or made available. RELP has
not received any notice of a default that has not been cured under any of the
documents described in clause (i) above or is in default respecting any payment
obligations thereunder beyond any applicable grace periods. All options of RELP
to purchase real property will be set forth on the RELP Disclosure Letter and
such options and RELP's rights thereunder are in full force and effect. All
joint venture agreements to which RELP is a party will be set forth on the RELP
Disclosure Letter and RELP is not in default with respect to any obligations,
which individually or in the aggregate are material, thereunder.

         5.18.    Development Rights.  Set forth in the RELP Disclosure Letter
will be a list of all material agreements entered into by RELP relating to the
development, rehabilitation, capital improvement or construction of office
buildings, industrial facilities  or other real estate properties, which
development or construction has not been substantially completed as of the date
of this Agreement. Such agreements, true and correct copies of all of which
will be delivered or made available to AIP prior to September 30, 1997, will be
listed in the RELP Disclosure Letter, have not been modified and are valid and
binding in accordance with their respective terms.

         5.19.    Convertible Securities.  To RELP's actual knowledge, RELP has
no outstanding options, warrants or other securities exercisable for, or
convertible into, RELP Interests, the terms of which would require any anti-
dilution adjustments by reason of the consummation of the transactions
contemplated hereby.

              ARTICLE VI .  REPRESENTATIONS AND WARRANTIES OF AIP

         AIP represents and warrants to RELP as set forth below.  As
contemplated below, an "AIP Disclosure Letter" will be delivered to RELP on or
before September 20, 1997.  The AIP Disclosure Letter shall provide the
information or exceptions described below. The AIP Disclosure Letter shall be
amended prior to Closing to cause such representations and warranties to be
materially true and correct on the Closing Date, but AIP shall remain liable
for any material breach of such representations and warranties reflected in
such amendment only as provided in Section 9.5(d), below.

         6.1.     Existence; Good Standing; Authority; Compliance with Law.
(a)  AIP is a real estate investment trust duly organized and  validly existing
under the laws of the State of Texas.   To AIP's actual knowledge, AIP is duly
licensed or qualified to do business and is in good standing under the laws of
any other state of the United States in which the character of the properties
owned or leased by it therein or in which the transaction of its business makes
such qualification necessary, except where the failure to be so qualified would
not have a material adverse effect on the business, results of operations or
financial condition of AIP and its subsidiaries taken as a whole (an "AIP
Material





                                       10
<PAGE>   11
Adverse Effect"). AIP has all requisite power and authority to own, operate,
lease and encumber its properties and carry on its business as now conducted.
Each of AIP's Subsidiaries is a corporation, limited liability company or
partnership duly organized, validly existing and in good standing under the
laws of its jurisdiction of incorporation or organization, has the requisite
power and authority to own its properties and to carry on its business as it is
now being conducted, and is duly qualified to do business and is in good
standing in each jurisdiction in which the ownership of its property or the
conduct of its business requires such qualification, except for jurisdictions
in which such failure to be so qualified or to be in good standing would not
have an AIP Material Adverse Effect.

         (b)     To AIP's actual acknowledge, neither AIP nor any AIP
Subsidiary is in violation of any order of any court, governmental authority or
arbitration board or tribunal, or any law, ordinance, governmental rule or
regulation to which AIP or any AIP Subsidiary or any of their respective
properties or assets is subject, where such violation would have an AIP
Material Adverse Effect. AIP and its Subsidiaries have obtained all licenses,
permits and other authorizations and have taken all actions required by
applicable law or governmental regulations in connection with their business as
now conducted, where the failure to obtain any such item or to take any such
action would have an AIP Material Adverse Effect. Copies of AIP's and its
Subsidiaries' Declaration of Trust, Articles of Incorporation, Bylaws,
organizational documents and partnership and joint venture agreements have been
or will be prior to September 30, 1997, delivered or made available to RELP and
such documents will be listed in the AIP Disclosure Letter and were or will be
true and correct when delivered or made available. For the purposes of the
immediately preceding sentence, the term "Subsidiary"shall include the entities
set forth in the AIP Disclosure Letter, which are all of AIP's Subsidiaries.

         6.2.     Authorization, Validity and Effect of Agreements.  AIP has
the requisite power and authority to enter into the transactions contemplated
hereby and to execute and deliver this Agreement and all other documents,
agreements and instruments related to the transactions contemplated by this
Agreement to which it is a party (the "AIP Ancillary Agreements"). Subject only
to the approval of the issuance of AIP Common Shares pursuant to the Merger
contemplated hereby by the holders of two-thirds of the outstanding AIP Common
Shares, present and voting thereon, the consummation by AIP of this Agreement,
the AIP Ancillary Agreements and the transactions contemplated hereby have been
duly authorized by all requisite action on the part of AIP. This Agreement
constitutes, and the AIP Ancillary Agreements (when executed and delivered
pursuant hereto for value received) will constitute, the valid and legally
binding obligations of AIP enforceable against AIP in accordance with their
respective terms, subject to Equitable Remedies.

         6.3.     Capitalization.  On June 15, 1997, the authorized capital
stock of AIP consists of 10,000,000 Common Shares. As of the date hereof, all
10,000,000 Common Shares are outstanding. AIP has no outstanding bonds,
debentures, notes or other obligations (other than to Realco), the holders of
which have the right to vote (or which are convertible into or exercisable for
securities having the right to vote) with the shareholders of AIP on any
matter. Except as set forth in the AIP Disclosure Letter, all such issued and
outstanding of AIP Common Shares are duly authorized, validly issued, fully
paid, nonassessable and free of preemptive rights. Except as set forth in the
AIP Disclosure Letter, there are not at the date of this Agreement any existing
options, warrants, calls, subscriptions, convertible securities, or other
rights, agreements or commitments which obligate AIP or any of its Subsidiaries
to issue, transfer or sell any shares or other equity interest of AIP or any





                                       11
<PAGE>   12
of its Subsidiaries except under any employee incentive plan approved by AIP's
shareholders. There are no agreements or understandings to which AIP is a party
with respect to the voting of any AIP Common Shares or which restrict the
transfer of any such shares, except in order to protect its REIT status.

         6.4.    Subsidiaries.  Except as set forth in the AIP Disclosure
Letter, AIP owns directly or indirectly each of the outstanding shares of
capital stock or all of the partnership or other equity interests of each of
AIP's Subsidiaries free and clear of all liens, pledges, security interests,
claims or other encumbrances other than liens imposed by local law which are
not material.

         6.5.    Other Interests.   Except as will be disclosed in the AIP
Disclosure Letter and except for interests in the AIP Subsidiaries, neither AIP
nor any AIP Subsidiary owns directly or indirectly any interest or investment
(whether equity or debt) in any corporation, partnership, joint venture,
business, trust or entity (other than investments in short-term investment
securities).

         6.6.    No Violation.   Neither the execution and delivery by AIP of
this Agreement nor the consummation by AIP of the transactions contemplated
hereby in accordance with the terms hereof, will: (i) conflict with or result
in a breach of any provisions of AIP's Declaration of Trust; (ii) violate, or
conflict with, or result in a breach of any provision of, or constitute a
default (or an event which, with notice or lapse of time or both, would
constitute a default) under, or result in the termination or in a right of
termination or cancellation of, or accelerate the performance required by, or
result in the creation of any lien, security interest, charge or encumbrance
upon any of the properties of AIP or its Subsidiaries under, or result in being
declared void, voidable or without further binding effect, any of the terms,
conditions or provisions of any note, bond, mortgage, indenture, deed of trust
or any license, franchise, permit, lease, contract, agreement or other
instrument, commitment or obligation to which AIP or any of its Subsidiaries is
a party, or by which AIP or any of its Subsidiaries or any of their properties
is bound or affected, except for any of the foregoing matters which,
individually or in the aggregate, would not have an AIP Material Adverse
Effect; or (iii) other than the Regulatory Filings require any consent,
approval or authorization of, or declaration, filing or registration with, any
domestic governmental or regulatory authority, except where the failure to
obtain such consent, approval or authorization of, or declaration, filing or
registration with, any governmental or regulatory authority would not have an
AIP Material Adverse Effect.

         6.7.    SEC Documents.   (a)  AIP has made available or will make
available to RELP prior to September 30, 1997, the registration statements of
AIP filed with the SEC in connection with public offerings of AIP securities
since January 1, 1994 and all exhibits, amendments and supplements thereto (the
"AIP Registration Statements"), and each registration statement, report, proxy
statement or information statement and all exhibits thereto prepared by it or
relating to its properties since the effective date of the latest AIP
Registration Statement, each in the form (including exhibits and any amendments
thereto) filed with the SEC (collectively, the "AIP Reports"). The AIP Reports,
which were or will be filed with the SEC in a timely manner, constitute all
forms, reports and documents required to be filed by AIP under the Securities
Laws.





                                       12
<PAGE>   13
         (b)     To AIP's actual knowledge, as of their respective dates, the
AIP Reports (i) complied as to form in all material respects with the
applicable requirements of the Securities Laws, and (ii) did not contain any
untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements made therein, in the
light of the circumstances under which they were made, not misleading. To AIP's
actual acknowledge, each of the consolidated balance sheets of AIP included in
or incorporated by reference into the AIP Reports (including the related notes
and schedules) fairly presents the consolidated financial position of AIP and
the AIP Subsidiaries as of its date and each of the consolidated statements of
income, retained earnings and cash flows of AIP included in or incorporated by
reference into the AIP Reports (including any related notes and schedules)
fairly presents the results of operations, retained earnings or cash flows, as
the case may be, of AIP and the AIP Subsidiaries for the periods set forth
therein (subject, in the case of unaudited statements, to normal year-end audit
adjustments which would not be material in amount or effect), in each case in
accordance with generally accepted accounting principles consistently applied
during the periods involved, except as may be noted therein and except, in the
case of the unaudited statements, as permitted by the Securities Laws.

         (c)     Except as and to the extent set forth on the consolidated
balance sheet of AIP and its Subsidiaries at March 31, 1997, including all
notes thereto, or as set forth in the AIP Reports, neither AIP nor any of the
AIP Subsidiaries has any material liabilities or obligations of any nature
(whether accrued, absolute, contingent or otherwise) that would be required to
be reflected on, or reserved against in, a balance sheet of AIP or in the notes
thereto, prepared in accordance with generally accepted accounting principles
consistently applied, except liabilities arising in the ordinary course of
business since such date which would not have an AIP Material Adverse Effect.

         6.8.     Litigation.   To AIP's actual knowledge, there are (i) no
continuing orders, injunctions or decrees of any court, arbitrator or
governmental authority to which AIP or any AIP Subsidiary is a party or by
which any of its properties or assets are bound or, to which any of its
directors, officers, or affiliates is a party or by which any of their
properties or assets are bound, and (ii) except as will be set forth in the AIP
Disclosure Letter, no actions, suits or proceedings pending against AIP or any
AIP Subsidiary or, to the knowledge of AIP, against any of its Trust Managers,
officers, or affiliates or, to the knowledge of AIP, threatened against AIP or
any AIP Subsidiary or against any of its Trust Managers, officers, or
affiliates, at law or in equity, or before or by any federal or state
commission, board, bureau, agency or instrumentality, that in the case of
clauses (i) or (ii) above are reasonably likely, individually or in the
aggregate, to have an AIP Material Adverse Effect.

         6.9.     Absence of Certain Changes.  Except as disclosed in the AIP
Reports filed with the SEC prior to the date hereof, (i) AIP and its
Subsidiaries have conducted their business only in the ordinary course of such
business (which, for purposes of this section only, shall include all
acquisitions of real estate properties and financing arrangements made in
connection therewith); (ii) there has not been any AIP Material Adverse Effect;
(iii) there has not been any declaration, setting aside or payment of any
dividend or other distribution with respect to the AIP Common Shares; and (iv)
there has not been any material change in AIP's accounting principles,
practices or methods.





                                       13
<PAGE>   14
         6.10.    Taxes.  (a)  Except as may be set forth in the AIP Disclosure
Letter, AIP and each of its Subsidiaries (i) has timely filed all federal,
state and foreign tax returns including, without limitation, information
returns and reports required to be filed by any of them for tax periods ended
prior to the date of this Agreement or requests for extensions have been timely
filed and any such request has been granted and has not expired and all such
returns are absolute and complete in all material respects, (ii) has paid or
accrued all taxes shown to be due and payable on such returns or which have
become due and payable pursuant to any assessment, deficiency notice, 30-day
letter or other notice received by it and (iii) has properly accrued all taxes
for such periods subsequent to the periods covered by such returns. Neither AIP
nor any of its Subsidiaries has received notice that the federal, state and
local income and franchise tax returns of AIP or any such Subsidiary has been
or will be examined by any taxing authority. Neither AIP nor any of its
Subsidiaries has executed or filed with the IRS or any other taxing authority
any agreement now in effect extending the period for assessment or collection
of any income or other taxes.

         (b)     Except as will be disclosed in the AIP Disclosure Letter,
neither AIP nor any of its Subsidiaries is a party to any pending action or
proceeding by any governmental authority for assessment or collection of taxes,
and no claim for assessment or collection of taxes has been asserted against
it. True, correct and complete copies of all federal, state and local income or
franchise tax returns filed by AIP and each of its Subsidiaries and all
communications relating thereto have been delivered to RELP or made available
to representatives of RELP or will be so delivered or made available prior to
September 30, 1997. AIP (i) has qualified to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable years ended December 31,
1985 through 1996, inclusive (ii) has operated, and intends to continue to
operate, in such a manner as to qualify to be taxed as a REIT pursuant to
Sections 856 through 859 of the Code for its taxable year ended on the
effective date of the Merger, and (iii) has not taken or omitted to take any
action which could result in, and each of the executive officers of AIP, each
acting in his respective capacity as such, has no actual knowledge of, a
challenge to its status as a REIT. AIP represents that each of its Subsidiaries
is a Qualified REIT Subsidiary as defined in Section 856 (i) of the Code.
Neither AIP nor any of its Subsidiaries holds any asset (i) the disposition of
which could be subject to rules similar to Section 1374 of the Code as a result
of an election under IRS Notice 88-19 or (ii) that is subject to a consent
filed pursuant to Section 341(f) of the Code and regulations thereunder. For
purposes of this Section 6.10, "taxes" includes any interest, penalty or
additional amount payable with respect to any tax.

         6.11.   Books and Records.  (a)  The books of account and other
financial records of AIP and its Subsidiaries are in all material respects
true, complete and correct, have been maintained in accordance with good
business practices, and are accurately reflected in all material respects in
the financial statements included in the AIP Reports.

         (b)     The minute books and other records of AIP and its Subsidiaries
contain in all material respects accurate records of all meetings and
accurately reflect in all material respects all other corporate action of the
shareholders and Trust Managers and any committees of the Board of Trust
Managers of AIP and its Subsidiaries.





                                       14
<PAGE>   15
         6.12.    Properties.  (a)  AIP and its Subsidiaries own fee simple
title to each of the real properties reflected on the most recent balance sheet
of AIP included in the AIP Reports or as may be identified in the AIP
Disclosure Letter (the "AIP Properties"), which are all of the real estate
properties owned by them, free and clear of Encumbrances. To AIP's actual
knowledge, the AIP Properties are not subject to any rights of way, written
agreements, laws, ordinances and regulations affecting building use or
occupancy, or reservations of an interest in title (collectively, "Property
Restrictions"), except for (i) Encumbrances and Property Restrictions that will
be set forth in the AIP Disclosure Letter, (ii) Property Restrictions imposed
or promulgated by law or any governmental body or authority with respect to
real property, including zoning regulations, provided they do not materially
adversely affect the current use of the property, (iii) Encumbrances and
Property Restrictions disclosed on existing title reports or surveys (in either
case copies of which title reports and surveys have been or will be delivered
or made available to RELP prior to September 30, 1997), and (iv) mechanics',
carriers', workmen's, repairmen's liens and other Encumbrances, Property
Restrictions and other limitations of any kind, if any, which have heretofore
been bonded (and that will be listed in the AIP Disclosure Letter) or which
individually or in the aggregate, do not exceed $100,000, do not materially
detract from the value of or materially interfere with the present use of any
of the AIP Properties subject thereto or affected thereby, and do not otherwise
materially impair business operations conducted by AIP and its Subsidiaries and
which have arisen or been incurred only in its construction activities or in
the ordinary course of business.

         (b)     Valid policies of title insurance have been issued insuring
AIP's or any of its Subsidiaries' fee simple title to the AIP Properties,
subject only to the matters disclosed above and as may be set forth in the AIP
Disclosure Letter, and such policies are, at the date hereof, in full force and
effect and no material claim has been made against any such policy. To AIP's
actual knowledge, except as will be set forth in the AIP Disclosure Letter, (i)
there is no certificate, permit or license from any governmental authority
having jurisdiction over any of the AIP Properties or any agreement, easement
or other right which is necessary to permit the lawful use and operation of the
buildings and improvements on any of the AIP Properties or which is necessary
to permit the lawful use and operation of all driveways, roads and other means
of egress and ingress to and from any of the AIP Properties that has not been
obtained and is not in full force and effect, or of any pending threat of
modification or cancellation of any of same; (ii) neither AIP nor its
Subsidiaries has received written notice of any material violation of any
federal, state or municipal law, ordinance, order, regulation or requirement
affecting any portion of any of the AIP Properties issued by any governmental
authority; (iii) there are no structural defects relating to the AIP Properties
and no AIP Properties whose building systems are not in working order in any
material respect; and (iv) there is (A) no physical damage to any AIP Property
in excess of $100,000 for which there is no insurance in effect covering the
cost of the restoration, (B) no current renovation to any AIP Property the cost
of which exceeds $100,000 and (C) no current restoration (excluding tenant
improvements) of any AIP Property the cost of which exceeds $100,000.

         (c)     Except as will be set forth in the AIP Disclosure Letter, AIP
or its Subsidiaries have received no notice to the effect that and there are no
(A) condemnation or rezoning proceedings that are pending or threatened with
respect to any of the AIP Properties or (B) any zoning, building or similar
laws, codes, ordinances, orders or regulations that are or will be violated by
the continued maintenance, operation or use of any buildings or other
improvements on any of the AIP Properties or by the continued maintenance,
operation or use of the parking areas in any material respect. All





                                       15
<PAGE>   16
work to be performed, payments to be made and actions to be taken by AIP or its
Subsidiaries prior to the date hereof pursuant to any agreement entered into
with a governmental body or authority in connection with a site approval,
zoning reclassification or other similar action relating to the AIP Properties
(e.g., Local Improvement District, Road Improvement District, Environmental
Mitigation) has been performed, paid or taken, as the case may be, and AIP is
not aware of any planned or proposed work, payments or actions that may be
required after the date hereof pursuant to such agreements, except as will be
set forth in the AIP Disclosure Letter.

         6.13.   Environmental Matters.  To the actual knowledge of AIP, none
of AIP, any of its Subsidiaries or, any other person has caused or permitted
(i) the unlawful presence of any Hazardous Materials on any of the AIP
Properties, or (ii) any unlawful spills, releases, discharges or disposal of
Hazardous Materials to have occurred or be presently occurring on or from the
AIP Properties as a result of any construction on or operation and use of such
properties, which presence or occurrence would, individually or in the
aggregate, have an AIP Material Adverse Effect; and in connection with the
construction on or operation and use of the AIP Properties, AIP and its
Subsidiaries have not failed to comply, in any material respect, with any
applicable local, state and federal environmental laws, regulations, ordinances
and administrative and judicial orders relating to the generation, recycling,
reuse, sale, storage, handling, transport and disposal of any Hazardous
Materials.

         6.14.   Labor Matters.   Neither AIP nor any of its Subsidiaries is a
party to, or bound by, any collective bargaining agreement, contract or other
agreement or understanding with a labor union or labor union organization.
There is no unfair labor practice or labor arbitration proceeding pending or,
to the knowledge of the executive officers of AIP, threatened against AIP or
its Subsidiaries relating to their business, except for any such proceeding
which would not have an AIP Material Adverse Effect. To the knowledge of AIP,
there are no organizational efforts with respect to the formation of a
collective bargaining unit presently being made or threatened involving
employees of AIP or any of its Subsidiaries.

         6.15.   No Brokers.  Except for the fee payable to Prudential
Securities Incorporated ("Prudential") as described in Section 6.16 below, AIP
has not entered into any contract, arrangement or understanding  with any
person or firm which may result in the obligation of AIP or RELP to pay any
finder's fees, brokerage or agent's commissions or other like payments in
connection with the negotiations leading to this Agreement or the consummation
of the transactions contemplated hereby. AIP is not aware of any claim for
payment of any finder's fees, brokerage or agent's commissions or other like
payments in connection with the negotiations leading to this Agreement or the
consummation of the transactions contemplated hereby.

         6.16.   Opinion of Financial Advisor.  AIP has retained Prudential to
review the transaction contemplated by this Agreement and to issue an opinion
as to the fairness to AIP, from a financial point of view, of the consideration
to be paid by AIP pursuant to the Merger.

         6.17.   RELP Share Ownership.  Except as may be set forth in the AIP
Disclosure Letter, neither AIP nor any of its Subsidiaries owns any RELP
Interests or other securities convertible into RELP interests.





                                       16
<PAGE>   17
         6.18.    AIP Common Shares.  The issuance and delivery by AIP of AIP
Common Shares in connection with the Merger and this Agreement have been duly
and validly authorized by all necessary action on the part of AIP except for
the approval of its shareholders contemplated by this Agreement. The AIP Common
Shares to be issued in connection with the Merger and this Agreement, when
issued in accordance with the terms of this Agreement, will be validly issued,
fully paid and nonassessable, except that shareholders may be subject to
further assessment with respect to certain claims for tort, contract, taxes,
statutory liability and otherwise in some jurisdictions to the extent such
claims are not satisfied by AIP.

         6.19.   Convertible Securities.  AIP has no outstanding options,
warrants or other securities exercisable for, or convertible into, shares of
AIP Common Shares, the terms of which would require any anti-dilution
adjustments by reason of the consummation of the transactions contemplated
hereby, except the preemptive rights held by certain clients of Morgan Stanley
Asset Management, Inc. and held by MS Real Estate Special Situations, Inc. and
the convertible debt securities held by Realco.

         6.20.   Related Party Transactions.  Set forth in the AIP Disclosure
Letter will be a list of all arrangements, agreements and contracts entered
into by AIP or any of its Subsidiaries with (i) any person who is an officer,
Trust Manager or affiliate of AIP or any of its Subsidiaries, any relative of
any of the foregoing or any entity of which any of the foregoing is an
affiliate or (ii) any person who acquired AIP Common Shares in a private
placement. The copies of such documents, all of which have been or will be
delivered or made available to RELP prior to September 30, 1997, are or will be
true, complete and correct when delivered or made available.

         6.21.   Contracts and Commitments.  The AIP Disclosure Letter will set
forth (i) all unsecured notes or other obligations of AIP and AIP Subsidiaries
which individually may result in total payments in excess of $100,000, (ii)
notes, debentures, bonds and other evidence of indebtedness which are secured
or collateralized by mortgages, deeds of trust or other security interests in
the AIP Properties or personal property of AIP and its Subsidiaries, and (iii)
each commitment entered into by AIP or any of its Subsidiaries which
individually may result in total payments or liability in excess of $100,000.
Copies of the foregoing have been or will be delivered or made available to
RELP prior to September 30, 1997, will be listed on the AIP Disclosure Letter
and are or will be materially true and correct when delivered or made
available. None of AIP or any of its Subsidiaries has received any notice of a
default that has not been cured under any of the documents described in clause
(i) or (ii) above or is in default respecting any payment obligations
thereunder beyond any applicable grace periods. All options of AIP or any of
its Subsidiaries to purchase real property will be set forth on the AIP
Disclosure Letter and such options and AIP's or its Subsidiaries' rights
thereunder are in full force and effect. All joint venture agreements to which
AIP or any of its Subsidiaries is a party will be set forth on the AIP
Disclosure Letter and AIP or its Subsidiaries are not in default with respect
to any obligations, which individually or in the aggregate are material,
thereunder.

         6.22.   Development Rights.  Set forth in the AIP Disclosure Letter
will be a list of all material agreements entered into by AIP or any of its
Subsidiaries relating to the development, rehabilitation, capital improvement
or construction of office buildings, industrial facilities or other real estate
properties which development or construction has not been substantially
completed as of





                                       17
<PAGE>   18
the date of this Agreement. Such agreements, true, complete and correct copies
of all of which have been or will be delivered or made available to RELP prior
to September 30, 1997, will be listed in the AIP Disclosure Letter.

         6.23.   Certain Payments Resulting From Transactions.  The execution
of, and performance of the transactions contemplated by, this Agreement will
not (either alone or upon the occurrence of any additional or subsequent
events) (i) constitute an event under any AIP Benefit Plan, policy, practice,
agreement or other arrangement or any trust or loan (the "Employee
Arrangements") that will or may result in any payment (whether of severance pay
or otherwise), acceleration, forgiveness of indebtedness, vesting,
distribution, increase in benefits or obligation to fund benefits with respect
to any employee, director or consultant of AIP or any of its Subsidiaries
unless such rights have been waived by any such person, or (ii) result in the
triggering or imposition of any restrictions or limitations on the right of AIP
or RELP to amend or terminate any Employee Arrangement and receive the full
amount of any excess assets remaining or resulting from such amendment or
termination, subject to applicable taxes. No payment or benefit which will be
required to be made pursuant to the terms of any agreement, commitment or AIP
Benefit Plan, as a result of the transactions contemplated by this Agreement,
to any officer, director or employee of AIP or any of its Subsidiaries, will be
characterized as an "excess parachute payment" within the meaning of Section
280G(b)(1) of the Code.

                            ARTICLE VII.  COVENANTS

         7.1.    Acquisition Proposals.   Prior to the Effective Time, RELP and
AIP each agree (i) that neither of them nor any of their Subsidiaries shall,
and each of them shall direct and use its best efforts to cause its respective
officers, General Partner, limited partners, Trust Managers, employees, agents,
affiliates and representatives (including, without limitation, any investment
banker, attorney or accountant retained by it or any of its Subsidiaries), as
applicable, not to, initiate, solicit or encourage, directly or indirectly, any
inquiries or the making or implementation of any proposal or offer (including,
without limitation, any proposal or offer to its shareholders) with respect to
a merger, acquisition, tender offer, exchange offer, consolidation or similar
transaction involving, or any purchase of all or any significant portion of the
assets or any equity securities (or any debt securities convertible into equity
securities) of, such party or any of its Subsidiaries, other than the
transactions contemplated by this Agreement (any such proposal or offer being
hereinafter referred to as an "Acquisition Proposal") or engage in any
negotiations concerning, or provide any confidential information or data to, or
have any discussions with, any person relating to an Acquisition Proposal, or
otherwise facilitate any effort or attempt to make or implement an Acquisition
Proposal; (ii) that it will immediately cease and cause to be terminated any
existing activities, discussions or negotiations with any parties conducted
heretofore with respect to any of the foregoing and each will take the
necessary steps to inform the individuals or entities referred to above of the
obligations undertaken in this Section 7.1; and (iii) that it will notify the
other party immediately if any such inquiries or proposals are received by, any
such information is requested from, or any such negotiations or discussions are
sought to be initiated or continued with, it; provided, however, that nothing
contained in this Section 7.1 shall prohibit the Board of Directors of the
General Partner of RELP (the "Board of Directors") or the Board of Trust
Managers from (x) furnishing information to or entering into discussions or
negotiations with, any person or entity that makes an unsolicited bona fide
Acquisition Proposal, if, and only to the extent that, (A) the Board





                                       18
<PAGE>   19
of Directors or Board of Trust Managers, as applicable, determines in good
faith that such action is required for it to comply with its fiduciary duties
to limited partners or shareholders, as applicable,  imposed by law as advised
by counsel, (B) prior to furnishing such information to, or entering into
discussions or negotiations with, such person or entity, such party provides
written notice to the other party to this Agreement to the effect that it is
furnishing information to, or entering into discussions with, such person or
entity, and (C) subject to any confidentiality agreement with such person or
entity (which such party determined in good faith was required to be executed
in order for the Board of Directors or Board of Trust Managers, as applicable,
to comply with its fiduciary duties to limited partners or shareholders, as
applicable,  imposed by law as advised by counsel), such party keeps the other
party to this Agreement informed of the status (but not the terms) of any such
discussions or negotiations; and (y) to the extent applicable, complying with
Rule 14e-2 promulgated under the Exchange Act with regard to an Acquisition
Proposal.

         Nothing in this Section 7.1 shall (i) permit any party to terminate
this Agreement (except as specifically provided in Article IX hereof), (ii)
permit any party to enter into any agreement with respect to an Acquisition
Proposal during the term of this Agreement (it being agreed that during the
term of this Agreement, no party shall enter into any agreement with any person
that provides for, or in any way facilitates, an Acquisition Proposal (other
than a confidentiality agreement in customary form)), or (iii) affect any other
obligation of any party under this Agreement.

         7.2.    Conduct of Businesses.

         (i)      Prior to the Effective Time, except as may be set forth in
the RELP Disclosure Letter or the AIP Disclosure Letter or as contemplated by
this Agreement, unless the other party has consented in writing thereto, AIP
and RELP:

         (a)     Shall use their reasonable efforts, and shall cause each of
                 their respective Subsidiaries to use their reasonable efforts,
                 to preserve intact their business organizations and goodwill
                 and keep available the services of their respective officers
                 and employees;

         (b)     Shall confer on a regular basis with one or more
                 representatives of the other to report operational matters of
                 materiality and, subject to Section 7.1, any proposals to
                 engage in material transactions;

         (c)     Shall promptly notify the other of any material emergency or
                 other material change in the condition (financial or
                 otherwise) of the  business, properties, assets or
                 liabilities, or any material governmental complaints,
                 investigations or hearings (or communications indicating that
                 the same may be contemplated), or the breach in any material
                 respect of any representation, warranty, covenant or agreement
                 contained herein;

         (d)     Shall not pay quarterly dividends or make distributions
                 payable with respect to the AIP Common Shares and RELP
                 Partnership Interests, respectively; and

         (e)     Shall promptly deliver to the other true and correct copies of
                 any report, statement or schedule filed with the SEC
                 subsequent to the date of this Agreement.





                                       19
<PAGE>   20
         (ii)    Prior to the Effective Time, except as may be set forth in the
RELP Disclosure Letter, unless AIP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, RELP:

         (a)     Shall conduct its operations according to its usual, regular
                 and ordinary course in substantially the same manner as
                 heretofore conducted;

         (b)     Shall not amend the RELP Organizational Documents;

         (c)     Shall not (i) except pursuant to the exercise of options,
                 warrants, conversion rights and other contractual rights
                 existing on the date hereof and disclosed pursuant to this
                 Agreement, issue any RELP Interests, make any distribution,
                 effect any recapitalization or other similar transaction, (ii)
                 grant, confer or award any option, warrant, conversion right
                 or other right not existing on the date hereof to acquire any
                 RELP Interest, (iii) increase any compensation or enter into
                 or amend any employment agreement with any of its present or
                 future officers or directors of the General Partner, or (iv)
                 adopt any new employee benefit plan or amend any existing
                 employee benefit plan in any material respect, except for
                 changes which are less favorable to participants in such
                 plans;

         (d)     Shall not declare, set aside or make any distribution or
                 payment with respect to any RELP Interest or directly or
                 indirectly redeem, purchase or otherwise acquire any RELP
                 Interest, or make any commitment for any such action;

         (e)     Shall not sell or otherwise dispose of (i) any RELP
                 Properties, or (ii) except in the ordinary course of business,
                 any of its other assets which are material, individually or in
                 the aggregate;

         (f)     Shall not make any loans, advances or capital contributions
                 to, or investments in, any other person;

         (g)     Shall not pay, discharge or satisfy any claims, liabilities or
                 obligations (absolute, accrued, asserted or unasserted,
                 contingent or otherwise), other than the payment, discharge or
                 satisfaction in the ordinary course of business consistent
                 with past practice or in accordance with their terms, of
                 liabilities reflected or reserved against in, or contemplated
                 by, the most recent consolidated financial statements (or the
                 notes thereto) of RELP included in the RELP Reports or
                 incurred in the ordinary course of business consistent with
                 past practice;

         (h)     Shall not enter into any commitment which individually may
                 result in total payments or liability by or to it in excess of
                 $250,000 in the case of any one commitment or in excess of
                 $500,000 for all commitments;





                                       20
<PAGE>   21
         (i)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment with any officer, director or
                 affiliate of RELP or  its General Partner except to the extent
                 the same occur in the ordinary course of business consistent
                 with past practice and would not have a RELP Material Adverse
                 Effect; and

         (j)     Shall not enter into or terminate any lease representing
                 annual revenues of $100,000 or more.

         (iii)   Prior to the Effective Time, except as may be set forth in the
AIP Disclosure Letter, unless RELP has consented (such consent not to be
unreasonably withheld or delayed) in writing thereto, AIP:

         (a)     Shall, and shall cause each of its Subsidiaries to, conduct
                 its operations according to their usual, regular and ordinary
                 course in substantially the same manner as heretofore
                 conducted;

         (b)     Shall not amend its Declaration of Trust or Bylaws except as
                 contemplated by this Agreement;

         (c)     Shall not (i) except pursuant to the exercise of options,
                 warrants, conversion rights and other contractual rights
                 (including AIP's existing dividend reinvestment plan) existing
                 on the date hereof and disclosed pursuant to this Agreement,
                 issue any shares of its capital stock, effect any share split,
                 reverse share split, share dividend, recapitalization or other
                 similar transaction, (ii) grant, confer or award any option,
                 warrant, conversion right or other right not existing on the
                 date hereof to acquire any shares of its capital shares
                 (except pursuant to any employee incentive plan approved by
                 shareholders), (iii) amend any employment agreement with any
                 of its present or future officers or Trust Managers, or (iv)
                 adopt any new employee benefit plan (including any share
                 option, share benefit or share purchase plan) except the
                 employee incentive plan to be voted on at its shareholder
                 meeting for the fiscal year ended December 31, 1995;

         (d)     Shall not declare, set aside or pay any dividend or make any
                 other distribution or payment with respect to any Common
                 Shares or directly or indirectly redeem, purchase or otherwise
                 acquire  any Common Shares or capital stock of any of its
                 Subsidiaries, or make any commitment for any such action;

         (e)     Except as will be set forth in the AIP Disclosure Letter,
                 shall not, and shall not permit any of its Subsidiaries to,
                 sell or otherwise dispose of (i) any AIP Properties or any of
                 its capital stock of or other interests in Subsidiaries or
                 (ii) except in the ordinary course of business, any of its
                 other assets which are material, individually or in the
                 aggregate;

         (f)     Shall not, and shall not permit any of its Subsidiaries to,
                 make any loans, advances or capital contributions to, or
                 investments in, any other person other than in connection with
                 the sale of properties;





                                       21
<PAGE>   22
         (g)     Shall not, and shall not permit any of its Subsidiaries to,
                 pay, discharge or satisfy any claims, liabilities or
                 obligations (absolute, accrued, asserted or unasserted,
                 contingent or otherwise), other than the payment, discharge or
                 satisfaction in the ordinary course of business consistent
                 with past practice or in accordance with their terms, of
                 liabilities reflected or reserved against in, or contemplated
                 by, the most recent consolidated financial statements (or the
                 notes thereto) of AIP included in the AIP Reports or incurred
                 in the ordinary course of business consistent with past
                 practice;

         (h)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment which individually may result in
                 total payments or liability by or to it in excess of $500,000
                 in the case of any one commitment or in excess of $500,000 for
                 all commitments; and

         (i)     Shall not, and shall not permit any of its Subsidiaries to,
                 enter into any commitment with any officer, Trust Manager or
                 affiliate of AIP or any of its Subsidiaries, except as herein
                 or in the AIP Disclosure Letter provided and except in the
                 ordinary course of business.

For purposes of this Section 7.2, any consent shall be deemed to be
unreasonably delayed if notice of consent or withholding of consent is not
received within three days of request.  Further, if no response is received by
the end of business on such third day, the party receiving the request shall be
deemed to have consented to such action.

         7.3     Meetings of Shareholders and Partners.  Each of AIP and RELP
will take all action necessary in accordance with applicable law and its
organizational documents  to convene a meeting of its shareholders or partners,
as applicable,  as promptly as practicable to consider and vote upon or
otherwise to obtain the consent of its shareholders or partners, as applicable,
to (i) in the case of AIP, approve this Agreement and the transactions
contemplated hereby, and (ii) in the case of RELP, approve this Agreement and
the transactions contemplated hereby. The Board of Trust Managers and the
General Partner shall each recommend such approval and AIP and RELP shall each
take all lawful action to solicit such approval, including, without limitation,
timely mailing the Proxy Statement/Prospectus (as defined in Section 7.7);
provided, however, that such recommendation or solicitation is subject to any
action taken by, or upon authority of, the Board of Trust Managers or the
General Partner, as the case may be, in the exercise of its good faith judgment
as to its fiduciary duties to its shareholders or partners, as applicable,
imposed by law as advised by counsel. AIP and RELP shall coordinate and
cooperate with respect to the timing of such meetings and shall use their best
efforts to hold such meetings on the same day.

         7.4.     Filings; Other Action.  Subject to the terms and conditions
herein provided, RELP and AIP shall: (a) use all reasonable efforts to
cooperate with one another in (i) determining which filings are required to be
made prior to the Effective Time with, and which consents, approvals, permits
or authorizations are required to be obtained prior to the Effective Time from
governmental or regulatory authorities of the United States and the several
states in connection with the execution and delivery of this Agreement and the
consummation of the transactions contemplated hereby and (ii) timely making all
such filings and timely seeking all such consents, approvals, permits or
authorizations; (b) use all reasonable efforts to obtain in writing any
consents required from third





                                       22
<PAGE>   23
parties in form reasonably satisfactory to RELP and AIP necessary to effectuate
the Merger; and (c) use all reasonable efforts to take, or cause to be taken,
all other action and do, or cause to be done, all other things necessary,
proper or appropriate to consummate and make effective the transactions
contemplated by this Agreement. If, at any time after the Effective Time, any
further action is necessary or desirable to carry out the purpose of this
Agreement, the proper officers and directors of AIP and the General Partner
shall take all such necessary action.

         7.5.    Inspection of Records.  From the date hereof to the Effective
Time, each of RELP and AIP shall allow all designated officers, attorneys,
accountants and other representatives of the other access at all reasonable
times to the records and  files, correspondence, audits and properties, as well
as to all information relating to commitments, contracts, titles and financial
position, or otherwise pertaining to the business and affairs of RELP and AIP
and their respective Subsidiaries.

         7.6.    Publicity.  RELP and AIP shall, subject to their respective
legal obligations (including requirements of stock exchanges and other similar
regulatory bodies), consult with each other, and use reasonable efforts to
agree upon the text of any press release before issuing any such press release
or otherwise making public statements with respect to the transactions
contemplated hereby and in making any filings with any federal or state
governmental or regulatory agency or with any national securities exchange with
respect thereto.

         7.7.    Registration Statement.  AIP and RELP shall cooperate and
promptly prepare and AIP shall file with the SEC as soon as practicable a
Registration Statement on Form S-4 (the "Form S-4") under the Securities Act,
with respect to the AIP Common Shares issuable in the Merger, a portion of
which Registration Statement shall also serve as the joint proxy statement with
respect to the meetings of the shareholders and partners, respectively, of AIP
and RELP in connection with the Merger (the "Proxy Statement/Prospectus"). The
respective parties will cause the Proxy Statement/Prospectus and the Form S-4
to comply as to form in all material respects with the applicable provisions of
the Securities Act, the Exchange Act and the rules and regulations promulgated
thereunder. AIP shall use all reasonable efforts, and RELP will cooperate with
AIP to have the Form S-4 declared effective by the SEC as promptly as
practicable.  AIP shall use its best efforts to obtain, prior to the effective
date of the Form S-4, all necessary state securities law or "Blue Sky" permits
or approvals required to carry out the transactions contemplated by this
Agreement and will pay all expenses incident thereto. AIP agrees that the Proxy
Statement/Prospectus and each amendment or supplement thereto, at the time of
mailing thereof and at the time of the respective meetings of shareholders and
partners, respectively, of AIP and RELP, or, in the case of the Form S-4 and
each amendment or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading; provided, however, that the foregoing shall not apply to the
extent that any such untrue statement of a material fact or omission to state a
material fact was made by AIP in reliance upon and in conformity with written
information concerning RELP furnished to AIP by RELP specifically for use in
the Proxy Statement/Prospectus. RELP agrees that the written information
provided by it specifically for inclusion in the Proxy Statement/Prospectus and
each amendment or supplement thereto, at the time of mailing thereof and at the
time of the respective meetings of shareholders and partners, respectively, of
AIP and RELP, or, in the case of written information provided by RELP
specifically for inclusion in the Form S-4





                                       23
<PAGE>   24
or any amendments or supplement thereto, at the time it is filed or becomes
effective, will not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading. AIP will advise RELP, promptly after it receives notice
thereof, of the time when the Form S-4 has become effective or any supplement
or amendment has been filed, the issuance of any stop order, the suspension of
the qualification of the AIP Common Shares issuable in connection with the
Merger for offering or sale in any jurisdiction, or any request by the SEC for
amendment of the Proxy Statement/Prospectus or the Form S-4 or comments thereon
and responses thereto or requests by the SEC for additional information.

         7.8.    Listing Application.  AIP shall promptly prepare and submit to
the NYSE a listing application covering the AIP Common Shares issuable in the
Merger, and shall use its reasonable efforts to obtain, prior to the Effective
Time, approval for the listing of such AIP Common Shares, subject to official
notice of issuance.

         7.9.    Further Action.  Each party hereto shall, subject to the
fulfillment at or before the Effective Time of each of the conditions of
performances set forth herein or the waiver thereof, perform such further acts
and execute such documents as may reasonably be required to effect the Merger.

         7.10.   Expenses.  Subject to Section 9.5, if the Merger is approved
by RELP's partners, all transaction costs of the proposed consolidation shall
be paid by AIP.  If three of the four limited partnerships party to the Proxy
Statement/Prospectus (the "Other RELPS") do not approve their proposed merger
into AIP, Realco shall reimburse AIP for AIP's expenses relating to the
proposed merger up to $250,000.  If RELP and the Other RELPS approve their
proposed merger into AIP, but the shareholders of AIP do not approve the
proposer merger, and if Realco voted its AIP Common Shares in favor of such
mergers, AIP will reimburse RELP and the Other RELPS for all expenses they
incurred in connection with the proposed merger.  Any expenses to be reimbursed
hereunder shall include, but not be limited to, costs of fairness opinions,
property appraisals, engineering and environmental reports, title policies,
accounting fees, legal fees, printing and solicitation expenses.  RELP will
bear the costs of preparing its initial fairness opinion, with later
reimbursement by AIP in the event the Merger is approved by RELP's partners.
If the limited partners of RELP fail to approve the proposed Merger, then
Realco will reimburse AIP for the RELP's expenses (to the extent paid by AIP)
as follows: the actual cost of such RELP's fairness opinion, legal fees up to
$80,000, and the actual cost or the Allocable Share  (if the actual cost is not
separately determined), of RELP's accounting fees, engineering and
environmental reports, printing and solicitation expenses.  Allocable Share,
for this purpose, shall be the ratio of such RELP's net book value of assets at
March 31, 1997 to the total net book value of all of the assets of RELP and the
Other RELPS at March 31, 1997.

         7.11.   Indemnification.  For a period of six years from and after the
Effective Time, AIP shall indemnify the partners, or agents of RELP who at any
time prior to the Effective Time were entitled to indemnification under the
Agreement of Limited Partnership of RELP existing on the date hereof to the
same extent as such partners or agents are entitled to indemnification under
such Agreement of Limited Partnership in respect of actions or omissions
occurring at or prior to the Effective Time (including, without limitation, the
transactions contemplated by this Agreement).





                                       24
<PAGE>   25
         7.12.   REIT Status.  From and after the date and until the Effective
Time, neither AIP nor RELP nor any of their respective Subsidiaries or other
affiliates shall (i) knowingly take any action, or knowingly fail to take any
action, that would jeopardize qualification of AIP as a REIT within the meaning
of Sections 856 through 859 of the Code; or (ii) enter into any contract,
agreement, commitment or arrangement with respect to the foregoing.

         7.13.   Survival of RELP Obligations; Assumption of RELP Liabilities
by AIP.  All of the obligations of RELP that are outstanding at the Closing
shall survive the Closing and shall not be merged therein. Upon the
consummation of the Merger, such obligations shall be assumed, automatically,
by AIP; provided, however, that such assumption shall not impose upon or expose
AIP to any liability for which RELP was not liable, and provided, further, that
AIP shall be entitled to the same defenses, offsets and counterclaims to which
RELP would have been entitled, but for the Merger.

         7.14.   Third Party Consents.  AIP and RELP each shall take all
necessary corporate and other action and will use its commercially reasonable
efforts to obtain the consents and applicable approvals from third parties that
may be required to enable it to carry out the transactions contemplated by this
Agreement.

         7.15.   Efforts to Fulfill Conditions.  AIP and RELP each shall use
commercially reasonable efforts to insure that all conditions precedent to its
obligations hereunder are fulfilled at or prior to the Closing.

         7.16.   Representations, Warranties and Conditions Prior to Closing.
AIP and RELP each shall use its commercially reasonable efforts to cause its
representations and warranties contained in this Agreement to be true and
correct on and as of the Closing Date in all material respects. Prior to
Closing, AIP and RELP each shall promptly notify the other in writing (i) if
any representation or warranty contained in this Agreement is discovered to be
or becomes untrue or (ii) if AIP or RELP fails to perform or comply with any of
its covenants or agreements contained in this Agreement or it is reasonably
expected that it will be unable to perform or comply with any of its covenants
or agreements contained in this Agreement.

         7.17.   Cooperation of the Parties.  AIP and RELP each will cooperate
with the other in supplying such information as may be reasonably requested by
the other in connection with obtaining consents or approvals to the
transactions contemplated by this Agreement.

         7.18.   Lock-Ups.  The General Partner shall use its best efforts
prior to the Closing to have each of its directors and officers and Realco
execute a 90-day lock-up agreement in a form (reasonably acceptable to RELP)
supplied to RELP by AIP. The executed agreements will be delivered to AIP at
the Closing.  AIP shall use its best efforts prior to the Closing to have each
of its Trust Managers and officers execute a 90-day lock-up agreement, in a
form (reasonably acceptable to AIP) supplied to AIP by RELP. The agreements
will be delivered to RELP at the Closing.





                                       25
<PAGE>   26
                           ARTICLE VIII.  CONDITIONS

         8.1.    Conditions to Each Party's Obligations to Effect the Merger.
The respective obligation of each party to effect the Merger shall be subject
to the fulfillment at or prior to the Closing Date of the following conditions:

         (a)     This Agreement and the transactions contemplated hereby shall
                 have been approved in the manner required by the Declaration
                 of Trust  and Bylaws and Agreement of Limited Partnership of
                 AIP and RELP, respectively, and by applicable law or by
                 applicable regulations of any stock exchange or other
                 regulatory body by the holders of the AIP Common Shares and
                 RELP Interests entitled to vote thereon.

         (b)     Neither of the parties hereto shall be subject to any order or
                 injunction of a court of competent jurisdiction which
                 prohibits the consummation of the transactions contemplated by
                 this Agreement. In the event any such order or injunction
                 shall have been issued, each party agrees to use its
                 reasonable efforts to have any such injunction lifted.

         (c)     The Form S-4 shall have become effective and all necessary
                 state securities law or "Blue Sky" permits or approvals
                 required to carry out the transactions contemplated by this
                 Agreement shall have been obtained and no stop order with
                 respect to any of the foregoing shall be in effect.

         (d)     AIP shall have obtained the approval for the listing of the
                 AIP Common Shares issuable in the Merger on the NYSE, subject
                 to official notice of issuance.

         (e)     All consents, authorizations, orders and approvals of (or
                 filings or registrations with) any governmental commission,
                 board, other regulatory body or third parties required in
                 connection with the execution, delivery and performance of
                 this Agreement shall have been obtained or made, except for
                 filings in connection with the Merger and any other documents
                 required to be filed after the Effective Time and except where
                 the failure to have obtained or made any such consent,
                 authorization, order, approval, filing or registration would
                 not have a material adverse effect on the business, results of
                 operations or financial condition of AIP and RELP (and their
                 respective Subsidiaries), taken as a whole, following the
                 Effective Time.

         8.2     Conditions to Obligations of RELP to Effect the Merger.  The
obligation of RELP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by
RELP:

         (a)     AIP shall have performed its agreements contained in this
                 Agreement required to be performed on or prior to the Closing
                 Date and the representations and warranties of AIP contained
                 in this Agreement shall be true and correct in all material
                 respects as of the Closing Date as if made on the Closing
                 Date, and RELP shall have received





                                       26
<PAGE>   27
                 a certificate of the President or an Executive or Senior Vice
                 President of AIP, dated the Closing Date, certifying to such
                 effect.

         (b)     RELP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by AIP and approved by
                 RELP, dated the Closing Date, to the effect that AIP met the
                 requirements for qualification and taxation as a REIT for its
                 taxable year ending December 31, 1985, and has met the
                 requirements for qualification and taxation as a REIT for its
                 taxable years 1986 through 1996; AIP's diversity of equity
                 ownership, operations through the Closing Date and proposed
                 method of operation for future periods should allow it to
                 qualify as a REIT for its taxable year ending December 31,
                 1997; and the discussion contained under the caption "Material
                 Federal Income Tax Consequences" in the Proxy
                 Statement/Prospectus accurately reflects existing law and
                 fairly addresses the material Federal income tax issues
                 described therein.  In rendering its opinion, said counsel
                 shall be entitled to rely as to any factual matter upon
                 certificates given by executive officers and other duly
                 authorized representatives of RELP and AIP and shall be
                 entitled to assume that the covenants set forth in Article VII
                 shall be fully complied with.

         (c)     From the date of the Agreement through the Effective Time,
                 there shall not have occurred any change in the financial
                 condition, business or operations of AIP and its Subsidiaries,
                 taken as a whole, that would have or would be reasonably
                 likely to have an AIP Material Adverse Effect other than any
                 such change that affects both RELP and AIP in a substantially
                 similar manner.

         (d)     The opinion of Houlihan addressed to RELP that the Purchase
                 Price is fair, from a financial point of view, to the partners
                 of RELP shall not have been withdrawn or materially modified.

         (e)     RELP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by AIP and approved by
                 RELP, dated the Closing Date, as to such customary matters as
                 RELP may reasonably request, such opinion to be reasonably
                 satisfactory to RELP.

         8.3     Conditions to Obligation of AIP to Effect the Merger.  The
obligations of AIP to effect the Merger shall be subject to the fulfillment at
or prior to the Closing Date of the following conditions, unless waived by AIP:

         (a)     RELP shall have performed its agreements contained in this
                 Agreement required to be performed on or prior to the Closing
                 Date and the representations and warranties of RELP contained
                 in this Agreement shall be true and correct in all material
                 respects as of the Closing Date as if made on the Closing Date
                 and AIP shall have received a certificate of the Chief
                 Executive Officer, President or an Executive Vice President of
                 the General Partner dated the Closing Date, certifying to such
                 effect.





                                       27
<PAGE>   28
         (b)     AIP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by RELP and approved by
                 AIP, dated the Closing Date, to the effect that the
                 consummation of the Merger will not result in AIP's failure to
                 continue to satisfy the requirements for qualification as a
                 REIT for federal income tax purposes. In rendering its
                 opinion, said counsel shall be entitled to rely as to any
                 factual matter upon certificates given by executive officers
                 and other duly authorized representatives of AIP and RELP and
                 shall be entitled to assume that the covenants of Article VII
                 shall be fully complied with.

         (c)     From the date of this Agreement through the Effective Time,
                 there shall not have occurred any change in the financial
                 condition, business or operations of RELP and its
                 Subsidiaries, taken as a whole, that would have or would be
                 reasonably likely to have an RELP Material Adverse Effect,
                 other than any such change that affects both RELP and AIP in a
                 substantially similar manner.

         (d)     Each person listed on Exhibit 8.3(d) attached hereto shall
                 have delivered to AIP a written agreement to the effect that
                 such person will not offer to sell, sell or otherwise dispose
                 of any shares of AIP Common Stock issued in the Merger,
                 except, in each case, pursuant to an effective registration
                 statement or in compliance with Rule 145, as amended from time
                 to time, or in a transaction which, in the opinion of legal
                 counsel reasonably satisfactory to AIP, is exempt from the
                 registration requirements of the Securities Act and that the
                 certificates representing the AIP shares issued to him or her
                 in the Merger may bear a legend to such effect.

         (e)     The opinion of Prudential addressed to the Board of Trust
                 Managers of AIP that the consideration to be paid by AIP
                 pursuant to the Merger is fair, from a financial point of
                 view, to AIP shall not have been withdrawn or materially
                 modified.

         (f)     AIP shall have received the opinion of Liddell, Sapp or
                 another recognized law firm selected by RELP and approved by
                 AIP, dated the Closing Date, as to such customary matters as
                 AIP may reasonably request, such opinion to be reasonably
                 satisfactory to AIP.

         (g)     The limited partners of at least two of the Other RELPS shall
                 have approved the merger of such limited partnership with and
                 into AIP.

                            ARTICLE IX.  TERMINATION

         9.1     Termination by Mutual Consent.  This Agreement may be
terminated and the Merger may be abandoned at any time prior to the Effective
Time, before or after the approval of this Agreement by the partners of RELP or
the shareholders of AIP or by the mutual written consent of AIP and RELP, with
the prior approval of their respective Board of Trust Managers and General
Partner.





                                       28
<PAGE>   29
         9.2     Termination by Either AIP or RELP.  This Agreement may be
terminated and the Merger may be abandoned by action of the General Partner of
RELP or the Board of Trust Managers of AIP if (i) the Merger shall not have
been consummated by March 31, 1998, (ii) a meeting of RELP's partners shall
have been duly convened and held and the approval of RELP's partners required
by Section 8.1(a) shall not have been obtained at such meeting or at any
adjournment thereof, (iii) a meeting of AIP's shareholders shall have been duly
convened and held and the approval of AIP's shareholders required by Section
8.1(a) shall not have been obtained at such meeting or at any adjournment
thereof, (iv) as a result of due diligence investigation by one of the parties
hereto, it is determined in good faith by such party that certain facts or
circumstances not previously known by such party constitute a Material Adverse
Effect on the business, results of operations or financial condition of the
other party, (v) a United States federal or state court of competent
jurisdiction or United States federal or state governmental, regulatory or
administrative agency or commission shall have issued an order, decree or
ruling or taken any other action permanently restraining, enjoining or
otherwise prohibiting the transactions contemplated by this Agreement and such
order, decree, ruling or other action shall have become final and
non-appealable, provided that the party seeking to terminate this Agreement
pursuant to this clause (v) shall have used all reasonable efforts to remove
such order, decree, ruling or injunction, or (vi) any of the conditions set
forth in Article VIII shall not have been satisfied,  and provided, in the case
of a termination pursuant to clause (i) or (vi) above, that the terminating
party shall not have breached in any material respect its obligations under
this Agreement in any manner that shall have proximately contributed to the
occurrence of the failure referred to in said clause. AIP and RELP each shall
(i) deliver its Disclosure Letter to one another not later than 5:00 P.M.,
Central Time, September 20, 1997, and (ii) shall complete its due diligence
investigations not later than 5:00 P.M., Central Time, on September 30, 1997.
Until October 7, 1997 (the period from the date of this Agreement through
October 7, 1997 being hereinafter referred to as the "Due Diligence Period"),
either party may terminate this Agreement without liability or penalty due to
the discovery of a fact or circumstance that reasonably could be expected to
constitute a Material Adverse Effect on the business, results of operations or
financial condition of the other party.  Unless objected to by the party
receiving the Disclosure Letter in writing prior to the expiration of the Due
Diligence Period, the receiving party shall be deemed to have approved the
other party's Disclosure Letter.

         9.3      Termination by RELP.  This Agreement may be terminated and
the Merger may be abandoned at any time prior to the Effective Time, before or
after the adoption and approval by the partners of RELP referred to in Section
8.1(a), by action of the General Partner, if (i) in the exercise of its good
faith judgment as to its fiduciary duties to its partners imposed by law, as
advised by counsel, the General Partner determines that such termination is
required by reason of a RELP Acquisition Proposal being made, (ii) the Board of
Trust Managers withdraws, materially modifies or changes in a manner materially
adverse to RELP its recommendations to AIP's shareholders of this Agreement or
the Merger, other than as a result of the occurrence of an event that in the
good faith judgment of the Board of Trust Managers has or is reasonably likely
to have a RELP Material Adverse Effect, (iii) the Board of Trust Managers
postpones the date scheduled for the meeting of shareholders of AIP to approve
this Agreement and the transactions contemplated hereby beyond March 31, 1998
or fails to set a date for such meeting by such date, except with the written
consent of RELP, (iv) there has been a breach by AIP of any representation or
warranty contained in this Agreement which would have or would be reasonably
likely to have an AIP Material Adverse Effect, which breach is not curable by
March 31,1998, or (v) there has been material breach of any of the





                                       29
<PAGE>   30
covenants or agreements set forth in this Agreement on the part of AIP, which
breach is not curable or, if curable, is not cured within 30 days after written
notice of such breach is given by RELP to AIP, or (vi) the condition set forth
in Section 8.3(g) is not satisfied..

         9.4     Termination by AIP.  This Agreement may be terminated and the
Merger may be abandoned at any time prior to the Effective Time, before or
after the approval by the shareholders of AIP referred to in Section 8.1(a), by
action of the Board of Trust Managers,  if (i) in the exercise of its good
faith judgment as to its fiduciary duties to its shareholders imposed by law,
as advised by counsel, the Board of Trust Managers determines that such
termination is required by reason of an AIP Acquisition Proposal being made,
(ii) the General Partner withdraws, materially modifies or changes in a manner
materially adverse to AIP its recommendation to RELP's partners of this
Agreement or the Merger, other than as a result of the occurrence of an event
that in the good faith judgment of the General Partner has or is reasonably
likely to have an AIP Material Adverse Effect, (iii) the General Partner
postpones the date scheduled for the meeting of partners of RELP to approve
this Agreement and the transactions contemplated hereby beyond March 31, 1998,
or fails to set a date for such meeting by such date, except with the written
consent of AIP, (iv) there has been a breach by RELP of any representation or
warranty contained in this Agreement which would have or would be reasonably
likely to have a RELP Material Adverse Effect, which breach is not curable by
March 31, 1998, or (v) there has been a material breach of any of the covenants
or agreements set forth in this Agreement on the part of RELP, which breach is
not curable or, if curable, is not cured within 30 days after written notice of
such breach is given by AIP to RELP.

         9.5.    Effect of Termination and Abandonment.  (a)  If an election to
terminate this Agreement is made pursuant to (i) Section 9.2(i) (except as a
result of a default or breach hereunder by AIP) or Section 9.2(ii), and a RELP
Acquisition Proposal relating to RELP shall have been made and, within one year
from the date of such termination, RELP consummates a RELP Acquisition Proposal
or enters into an agreement to consummate a RELP Acquisition Proposal which is
subsequently consummated, or (ii) Section 9.3(i), RELP shall pay to AIP,
provided that AIP was not in material breach of its obligations hereunder at
the time of such termination, as liquidated damages and not as a penalty or
forfeiture, an amount equal to the lesser of (m) $415,000  (the "Liquidated
Damages Amount") and (n) the sum of (1) the maximum amount that can be paid to
AIP without causing AIP to fail to meet the requirements of Sections 856(c)(2)
and (3) of the Code determined as if the payment of such amount did not
constitute income described in Sections 856(c)(2)(A)-(H) and 856(c)(3)(A)-(I)
of the Code ("Qualifying Income"), as determined by AIP's certified public
accountants, plus (2) an amount equal to the Liquidated Damages Amount less the
amount payable under clause (1) above in the event AIP receives a letter from
AIP's counsel indicating that AIP has received a ruling from the IRS to the
effect that Liquidated Damages Amount payments constitute Qualifying Income. In
addition to the Liquidated Damages Amount, AIP shall be entitled to receive
from RELP (or its successor in interest) all documented out-of-pocket costs and
expenses, up to a maximum of $207,500  in connection with this Agreement and
the transactions contemplated hereby (the "AIP Expenses") incurred by AIP. The
payments to which AIP is entitled under this Section 9.5(a) shall be its sole
remedy with respect to the termination of the Agreement under the circumstances
contemplated in this Section 9.5(a).





                                       30
<PAGE>   31
         (b)     If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.3(c) not
being satisfied), RELP shall, provided that AIP was not in material breach of
its obligations hereunder at the time of such termination, pay AIP for the AIP
Expenses, up to a maximum of $207,500, although it shall not be required to pay
the Liquidated Damages Amount, which payment of the AIP Expenses shall be AIP's
sole remedy for termination of the Agreement in such circumstances.

         (c)     If an election to terminate this Agreement is made pursuant to
(i) Section 9.2(i) (except as a result of a default or breach hereunder by
RELP) or Section 9.2(iii), and an AIP Acquisition Proposal relating to AIP
shall have been made and, within one year from the date of such termination,
AIP consummates an AIP Acquisition Proposal or enters into an agreement to
consummate an AIP Acquisition Proposal which is subsequently consummated, or
(ii) Section 9.4(i), AIP shall pay to RELP, provided that RELP was not in
material breach of its obligations hereunder at the time of such termination,
as liquidated damages and not as a penalty or forfeiture, an amount equal to
the Liquidated Damages Amount. In addition to the Liquidated Damages Amount,
RELP shall be entitled to receive from AIP (or its successor in interest) all
documented out-of-pocket costs and expenses, up to a maximum of $207,500, in
connection with this Agreement and the transactions contemplated hereby (the
"RELP Expenses" and, together with the AIP Expenses, the "Expenses")  incurred
by RELP. The payments to which RELP is entitled under this Section 9.5(c) shall
be its sole remedy with respect to the termination of the Agreement under the
circumstances contemplated in this Section 9.5(c)

         (d)     If an election to terminate this Agreement is made pursuant to
Section 9.2(i) (as a result of the condition set forth in Section 8.2(c) not
being satisfied), AIP shall, provided that RELP was not in material breach of
its obligations hereunder at the time of such termination, pay RELP for the
RELP Expenses, up to a maximum of $207,500, although it shall not be required
to pay the Liquidated Damages Amount, which payment of the RELP Expenses shall
be RELP's sole remedy for termination of the Agreement in such circumstances.

         (e)     If this Agreement is terminated pursuant to Section 9.3(iv),
Section 9.3(v), Section 9.4(iv), or Section 9.4(v), the non-terminating party
shall, provided that the terminating party was not in material breach of its
obligations hereunder at the time of such termination, pay the terminating
party all Expenses, up to a maximum of $207,500, incurred by it and the
non-terminating party shall remain liable to the terminating party for its
breach.

         (f)      If either party terminates this Agreement during the Due
Diligence Period described in Section 9.2 above other than for a due diligence
related reason, the non-terminating party shall be entitled to receive the
Liquidated Damages Amount and the Expenses as provided in this Article IX.

         (g)     RELP agrees to amend this Section 9.5 at the request of AIP in
order to (x) maximize the portion of the Liquidated Damages Amount that may be
distributed to AIP hereunder without causing AIP to fail to meet the
requirements of Sections 856(c)(2) and (3) of the Code or (y) improve AIP's
chances of securing a favorable ruling described in this Section 9.5, provided
that no such amendment may result in any additional cost or expense to such
other party.





                                       31
<PAGE>   32
         (h)     In the event of termination of this Agreement and the
abandonment of the Merger pursuant to this Article IX, all obligations of the
parties hereto shall terminate, except the obligations of the parties pursuant
to this Section 9.5 and Section 7.10 and except for the provisions of Section
10.3, 10.4, 10.5, 10.6, 10.7, 10.9, 10.10, 10.13, 10.14 and 10.16. In the event
AIP or RELP has received the Liquidated Damages Amount, such recipient shall
not assert or pursue in any manner, directly or indirectly, any claim or cause
of action against the other party hereto or any of its officers, Trust
Managers, or  General Partners, as applicable, based in whole or part upon its
or their receipt, consideration, recommendation or approval of an Acquisition
Proposal or the exercise by AIP of its right to termination under Section
9.4(i) or the exercise by RELP of its right to termination under Section
9.3(i).  Notwithstanding the foregoing, in the event AIP or RELP is required to
file suit to seek all or a portion of such Liquidated Damages Amount, and it
ultimately succeeds, it shall be entitled to all expenses, including attorney's
fees and expenses, which it has incurred in enforcing its right hereunder.

         (i)     If either party willfully fails to perform its duties and
obligations under this Agreement, the non- breaching party is additionally
entitled to all remedies available to it at law or in equity and to recover its
expenses from the breaching party.

         9.6     Extension; Waiver.  At any time prior to the Effective Time,
any party hereto, by action taken by its Board of Trust Managers or General
Partner, as applicable, may, to the extent legally allowed, (i) extend the time
for the performance of any of the obligations or other acts of the other
parties hereto, (ii) waive any inaccuracies in the representations and
warranties made to such party contained herein or in any document delivered
pursuant hereto and (iii) waive compliance with any of the agreements or
conditions for the benefit of such party contained herein. Any agreement on the
part of a party hereto to any such extension or waiver shall be valid only if
set forth in an instrument in writing signed on behalf of such party.

                         ARTICLE X.  GENERAL PROVISIONS

         10.1.   Nonsurvival of Representations, Warranties and Agreements.
All representations, warranties and agreements in this Agreement or in any
instrument delivered pursuant to this Agreement shall not survive the Merger;
provided, however, that the agreements contained in Article IV, the last
sentence of Section 7.4 and Sections 7.10, 7.11, 7.12, 7.13, 7.14, 7.15 and
7.16 and this Article X shall survive the Merger.

         10.2.    Notices.  Any notice required to be given hereunder shall be
in writing and shall be sent by facsimile transmission (confirmed by any of the
methods that follow), courier service (with proof of service), hand delivery or
certified or registered mail (return receipt requested and first-class postage
prepaid) and addressed as follows:

         If to AIP:
         American Industrial Properties REIT
         6220 N. Beltline Road, Suite 205
         Irving, Texas 75063
         Attention: Charles W. Wolcott, President
         Telecopy: (972) 550-6037





                                       32
<PAGE>   33
         If to RELP:
         USAA Real Estate Company
         8000 I-H 10 West, Suite 600
         San Antonio, Texas 78230
         Attention: Patrick Duncan, Senior Vice-President
         Telecopy: (210) 498-6214

or to such other address as any party shall specify by written notice so given,
and such notice shall be deemed to have been delivered as of the date so
delivered.

         10.3.   Assignment; Binding Effect; Benefit.  Neither this Agreement
nor any of the rights, interests or obligations hereunder shall be assigned by
any of the parties hereto (whether by operation of law or otherwise) without
the prior written consent of the other parties. Subject to the preceding
sentence, this Agreement shall be binding upon and shall inure to the benefit
of the parties hereto and their respective successors and assigns.
Notwithstanding anything contained in this Agreement to the contrary, except as
provided in the following sentence, nothing in this Agreement, expressed or
implied, is intended to confer on any person other than the parties hereto or
their respective heirs, successors, executors, administrators and assigns any
rights, remedies, obligations or liabilities under or by reason of this
Agreement. The provisions of Article IV and Sections 7.11, 7.12, 7.13, 7.14 and
7.15 (collectively, the "Third Party Provisions") shall benefit the persons
identified therein, but the aggregate liability of AIP with respect thereto
shall not exceed the amount specified in Article IX.

         10.4.   Entire Agreement.  This Agreement, the Exhibits, the RELP
Disclosure Letter, the AIP Disclosure Letter, the RELP Ancillary Agreements,
the AIP Ancillary Agreements and any documents delivered by the parties in
connection herewith constitute the entire agreement among the parties with
respect to the subject matter hereof and supersede all prior agreements and
understandings among the parties with respect thereto. No addition to or
modification of any provision of this Agreement shall be binding upon any party
hereto unless made in writing and signed by all parties hereto.

         10.5.   Confidentiality.  (a)  As used herein, "Confidential Material"
means, with respect to either party hereto (the "Providing Party"), all
information (written or oral) furnished (whether before or after the date
hereof) by the Providing Party and its directors, officers, employees,
affiliates or representatives of advisors, including counsel, lenders and
financial advisors (collectively, the "Providing Party Representatives") to the
other party hereto (the "Receiving Party") or such Receiving Party's directors,
officers, employees, affiliates or representatives of advisors, including
counsel, lenders and financial advisors or the Receiving Party's potential
sources of financing for the transactions contemplated by this Agreement
(collectively "the Receiving Party Representatives") and all analyses,
compilations, forecasts and other studies or other documents prepared by the
Providing Party or the Providing Party Representatives in connection with its
or their review of the transactions contemplated by this Agreement which
contain or reflect such information. The term "Confidential Material" does not
include, however, information which (i) at the time of disclosure or thereafter
is generally available to and known by the public other than as a result of a
disclosure directly or indirectly by the Receiving Party or the Receiving Party
Representatives in violation of this Agreement, (ii) at the time of disclosure
was available on a nonconfidential basis from a source





                                       33
<PAGE>   34
other than the Providing Party or the Providing Party Representatives,
providing that such source is not and was not bound by a confidentiality
agreement with the Providing Party, (iii) was known by the Receiving Party
prior to receiving the Confidential Material from the Providing Party or has
been independently acquired or developed by the Receiving Party without
violating any of its obligations under this Agreement, or (iv) is contained in
any RELP Reports or AIP Reports or Proxy Statement/Prospectus.

         (b)     Subject to paragraph (c) below or except as required by law,
the Confidential Material will be kept confidential and will not, without the
prior written consent of the Providing Party, be disclosed by the Receiving
Party or its Representatives, in whole or in part and will not be used by the
Receiving Party or its Representatives, directly or indirectly, for any purpose
other than in connection with this Agreement, the Merger or the evaluating,
negotiating or advising with respect to a transaction contemplated herein.
Moreover, each Receiving Party agrees to transmit Confidential Material to its
Representatives only if and to the extent that such Representatives need to
know the Confidential Material for purposes of such transaction and are
informed by such Receiving Party of the confidential nature of the Confidential
Material and of the terms of this Section.

         (c)     In the event that either Receiving Party, its Representatives
or anyone to whom such Receiving Party or its Representatives supply the
Confidential Material, are requested or required (by oral questions,
interrogatories, requests for information or documents, subpoena, civil
investigative demand, any informal or formal investigation by any government or
governmental agency or authority or otherwise in connection with legal
processes) to disclose any Confidential Material, such Receiving Party agrees
(i) to immediately notify the Providing Party of the existence, terms and
circumstances surrounding such a request, (ii) to consult with the Providing
Party on the advisability of taking legally available steps to resist or narrow
such request and (iii) if disclosure of such information is required, to
furnish only that portion of the Confidential Material which, in the opinion of
such Receiving Party's counsel, such Receiving Party is legally compelled to
disclose and to cooperate with any action by the Providing Party to obtain an
appropriate protective order or otherwise reliable assurances that confidential
treatment will be accorded the Confidential Material (it being agreed that the
Providing Party shall reimburse the Receiving Party for all reasonable
out-of-pocket expenses incurred by the Receiving Party in connection with such
cooperation).

         (d)     In the event of the termination of this Agreement in
accordance with its terms, promptly upon request from either Providing Party,
the Receiving Party shall, except to the extent prevented by law, redeliver to
the Providing Party or destroy all tangible Confidential Material and will not
retain any copies, extracts or other reproductions thereof in whole or in part.
Any such destruction shall be certified in writing to the Providing Party by an
authorized officer of the Receiving Party supervising the same. Notwithstanding
the foregoing, each Receiving Party and one Representative designated by each
Receiving Party shall be permitted to retain one permanent file copy of each
document constituting Confidential Material.

         (e)     Each party hereto further agrees that if this Agreement is
terminated in accordance with its terms, until one year from the date of
termination, (1) it will not offer to hire or hire any person currently or
formerly employed by the other party with whom such party has had contact prior
hereto other than persons whose employment shall have been terminated by such
other party prior to the date of such offer to hire or hiring and (2) neither
it nor its affiliates shall directly or indirectly,





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<PAGE>   35
(a) (w) solicit, seek or offer to effect or effect, (x) negotiate with or
provide any information to the Board of Trust Managers or General Partner, as
applicable, of the other party, or officer of the other party or any
shareholder or partner, as applicable, of the other party with respect to, (y)
make any statement or proposal, whether written or oral, either alone or in
concert with others, to the Board of Trust Managers or Board of Directors of
the General Partner of the other party, any director, Trust Manager or officer
of the other party or any shareholder or partner of the other party or any
other person with respect to, or (z) make any public announcement (except as
required by law in respect of actions permitted hereby) or proposal or offer
whatsoever (including, but not limited to, any "solicitation"of "proxies"as
such terms are defined or used in Regulation 14A of the Exchange Act) with
respect to, (i) any form of business combination or similar or other
extraordinary transaction involving the other party or any affiliate thereof,
including, without limitation, a merger, tender or exchange offer or
liquidation of the other party's assets, (ii) any form of restructuring,
recapitalization or similar transaction with respect to the other party or any
affiliate thereto, (iii) any purchase of any securities or assets, or rights or
options to acquire any securities or assets (through purchase, exchange,
conversion or otherwise), of the other party or any affiliate thereof, (iv) any
proposal to seek representation on the Board of Trust Managers or the Board of
Directors of the General Partner, as  applicable, or otherwise to seek to
control or influence the management, Board of Trust Managers or the Board of
Directors of the General Partner, as applicable, or policies of the other party
or any affiliate thereof, (v) any request or proposal to waive, terminate or
amend the provisions of this Section 10.5 or (vi) any proposal or other
statement inconsistent with the terms of this Section 10.5 or (b) instigate,
encourage, join, act in concert with or assist (including, but not limited to,
providing or assisting in any way in the obtaining of financing for, or acting
as a joint or co-bidder for the other party with) any third party to do any of
the foregoing, unless and until such party has received the prior written
invitation or approval of a majority of the Board of Trust Managers or the
General Partner, as applicable, to do any of the foregoing; provided that
without such invitation or approval, either party may at any time, on a
confidential non-public basis, submit to the Chief Executive Officer of AIP or
the General Partner, as applicable, a proposal to (a) amend any of the
provisions of this Section 10.5(e) or (b) effect a business combination or
other extraordinary transaction with the other party providing for the
acquisition of all or substantially all of the assets or the securities of the
other party, including, without limitation, a merger, tender offer or exchange
offer. Each party hereto agrees that it will not agree with any third party to
waive its rights under this Section 10.5.

         10.6.   Amendment.  This Agreement may be amended by the parties
hereto, by action taken by the Board of Trust Managers or the Board of
Directors of the General Partner, as applicable, at any time before or after
approval of this Agreement or any other matter presented in connection with the
Merger by the shareholders of AIP and partners of RELP, but after any such
approval, no amendment shall be made which by law requires the further approval
of shareholders or partners, as applicable, without obtaining such further
approval. This Agreement may not be amended except by an instrument in writing
signed on behalf of each of the parties hereto.

         10.7.   Governing Law.  This Agreement shall be governed by and
construed in accordance with the laws of the State of Texas without regard to
its rules of conflict of laws. Each of AIP and RELP hereby irrevocably and
unconditionally consents to submit to the exclusive jurisdiction of the courts
of the State of Texas and of the United States District Court, Northern
District of Texas (the "Texas Courts") for any litigation arising out of or
relating to this Agreement and the transactions contemplated hereby (and agrees
not to commence any litigation relating thereto except in such





                                       35
<PAGE>   36
courts), waives any objection to the laying of venue of any such litigation in
the Texas Courts and agrees not to plead or claim in any Texas Court that such
litigation brought therein has been brought in an inconvenient forum.

         10.8.   Counterparts.  This Agreement may be executed by the parties
hereto in separate counterparts, each of which when so executed and delivered
shall be an original, but all such counterparts shall together constitute one
and the same instrument. Each counterpart may consist of a number of copies
hereof each signed by less than all, but together signed by all of the parties
hereto.

         10.9.   Headings.  Heading of the Articles and Sections of this
Agreement are for the convenience of the parties only and shall be given no
substantive or interpretive effect whatsoever.

         10.10.  Interpretation.  In this Agreement, unless the context
otherwise requires, words describing the singular number shall include the
plural and vice versa, and words denoting any gender shall include all genders
and words denoting natural persons shall include corporations and partnerships
and vice versa.

         10.11.  Waivers.  Except as provided in this Agreement, no action
taken pursuant to this Agreement, including, without limitation, any
investigation by or on behalf of any party, shall be deemed to constitute a
waiver by the party taking such action of compliance with any representations,
warranties, covenants or agreements contained in this Agreement. The waiver by
any party hereto of a breach of any provision hereunder shall not operate or be
construed as a waiver of any prior or subsequent breach of the same or any
other provision hereunder.

         10.12.  Incorporation.  The RELP Disclosure Letter and the AIP
Disclosure Letter and all Exhibits and Schedules attached hereto and thereto
and referred to herein and therein are hereby incorporated herein and made a
part hereof for all purposes as if fully set forth herein.

         10.13.  Severability.    If any provision of this Agreement is held to
be illegal, invalid or unenforceable under any current or future law, and if
the rights or obligations of the parties under this Agreement would not be
materially and adversely affected thereby, such provision shall be fully
separable, and this Agreement shall be construed and enforced as if such
illegal, invalid or unenforceable provision had never comprised a part thereof,
and the remaining provisions of this Agreement shall remain in full force and
effect and shall not be affected by the illegal, invalid or unenforceable
provision or by its severance therefrom.  In lieu of such illegal, invalid or
unenforceable provision, there shall be added automatically as a part of this
Agreement, a legal, valid and enforceable provision as similar in terms to such
illegal, invalid or unenforceable provision as may be possible, and the parties
hereto request the court or any arbitrator to whom disputes relating to this
Agreement are submitted to reform the otherwise illegal, invalid or
unenforceable provision in accordance with this Section 10.13.

         10.14.  Enforcement of Agreement.  The parties hereto agree that
irreparable damage would occur in the event that any of the provisions of this
Agreement was not performed in accordance with its specific terms or was
otherwise breached. It is accordingly agreed that the parties shall be entitled
to an injunction or injunctions to prevent breaches of this Agreement and to
enforce specifically the





                                       36
<PAGE>   37
terms and provisions hereof in any Texas Court, this being in addition to any
other remedy to which they are entitled at law or in equity.

         10.15.  Subsidiaries.  As used in this Agreement, the word
"Subsidiary" when used with respect to any party means any corporation,
partnership, joint venture, business trust or other entity, of which such party
directly or indirectly owns or controls at least a majority of the securities
or other interests having by their terms ordinary voting power to elect a
majority of the board of directors or others performing similar functions with
respect to such corporation or other organization.

         10.16.  Non-Recourse.  Neither the officers, Trust Managers nor
shareholders of AIP shall be personally bound or have any personal liability
hereunder. RELP shall look solely to the assets of AIP for satisfaction of any
liability of AIP with respect to this Agreement and the Ancillary Agreements to
which it is a party. RELP will not seek recourse or commence any action against
any of the shareholders of AIP or any of their personal assets, and will not
commence any action for money judgments against any of the Trust Managers or
officers of AIP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of AIP hereunder or thereunder. The
partners of RELP shall not be personally bound or have any personal liability
hereunder. AIP shall look solely to the assets of RELP for satisfaction of any
liability of RELP with respect to this Agreement and the Ancillary Agreements
to which it is a party. AIP will not seek recourse or commence any action
against any of the partners of RELP or any of their personal assets, and will
not commence any action for money judgments against any of the directors or
officers of RELP or seek recourse against any of their personal assets, for the
performance or payment of any obligation of RELP hereunder or thereunder.

         IN WITNESS WHEREOF, the parties have executed this Agreement and
caused the same to be duly delivered on their behalf on the day and year first
written above.

                           AMERICAN INDUSTRIAL PROPERTIES REIT


                           /s/ Charles W. Wolcott                             
                           ---------------------------------------------------
                           Charles W. Wolcott, President and
                           Chief Executive Officer


                           USAA INCOME PROPERTIES IV LIMITED PARTNERSHIP

                           By:    USAA Properties IV, Inc., Its General Partner



                                  /s/ T. Patrick Duncan                       
                                  --------------------------------------------
                                  T. Patrick Duncan
                                  Senior Vice President - Operations






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