<PAGE>

                                                                 EXHIBIT 10.aa

                                AGREEMENT OF SALE


         AGREEMENT OF SALE (this "Agreement") made this 5th day of April, 2001
by and between NEW JERSEY ASSOCIATES, a New Jersey general partnership
("Seller") (and FAWN REALTY L.L.C., a New Jersey limited liability company
("Buyer").

                                    WITNESS:

         NOW THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are acknowledged, the parties agree as follows:

         1. SALE AND PURCHASE. Seller agrees to sell and convey to Buyer, and
Buyer agrees to purchase from Seller, upon the terms and conditions set forth in
this Agreement:

                   (a) REAL PROPERTY. Those certain lots or parcels of ground
situate in the State of New Jersey and more fully described by metes and bounds
on Exhibit "A" to this Agreement, together with the buildings and improvements
situate thereon (the "Premises"), together with all the rights and easements
appurtenant to the Premises, including any right, title and interest of Seller
(if any) in and to adjacent streets and rights-of-way; and

                   (b) PERSONAL PROPERTY. The fixtures, furnishings, equipment
and other items of personal property owned by Seller and located on, and used in
connection with the operation of, the Premises which are listed on Exhibit "B"
to this Agreement (collectively, the "Tangible Personal Property"); and

                   (c) INTANGIBLE PERSONAL PROPERTY. The interests of Seller in
the intangible personal property listed below:

                       (i) all existing surveys, blueprints, drawings, plans and
specifications (including, without limitation, structural, HVAC, mechanical and
plumbing plans and specifications) and other similar documentation for or with
respect to the Premises or any part thereof (all to the extent assignable or
transferable), to the extent in the possession of Seller;

                       (ii) all warranties and guaranties issued in connection
with the Premises (all to the extent assignable or transferable);

                       (iii) all consents, authorizations, variances or waivers,
licenses, permits and approvals from any governmental or quasi-governmental
agency, department, board, commission, bureau or other instrumentality (all to
the extent assignable or transferable) with respect to the Premises; and

<PAGE>

                       (iv) all of Seller's rights, title and interests in and
to the Existing Leases, as hereinafter defined.

(all of the foregoing, collectively, the "Intangible Personal Property").

                   (d) PERSONAL PROPERTY. The Tangible Personal Property and the
Intangible Personal Property are sometimes collectively referred to in this
Agreement as the "Personal Property."

         2. PURCHASE PRICE. The purchase price to be paid by Buyer to Seller for
the Premises and the Personal Property is the sum of Four Million Dollars
($4,000,000.00) (the "Purchase Price"). The Purchase Price shall be paid as
follows:

                  (a)      DEPOSIT.

                           (i)      The sum of One Hundred Thousand  Dollars
($100,000.00)  (the "Deposit") upon the execution of this Agreement.

                           (ii)     Buyer shall deliver the Deposit by the
delivery of Buyer's certified check, by bank check, subject to collection, or by
wire transfer of funds payable to the order of Chicago Title Insurance Company
(the "Escrowee"). The Escrowee shall immediately present Buyer's checks for
collection, if applicable, and then, pending consummation of this transaction,
hold the Deposit in escrow in accordance with the provisions of Paragraph 21.

                  (b) CLOSING PAYMENT. The balance of the Purchase Price (the
"Closing Payment") at closing (the "Closing") by wire transfer of immediate
United States federal funds to Seller's account at a bank designated by Seller.

        3. CLOSING. The Closing shall take place on July 15, 2001 ("Closing
Date") at the offices of Seller's counsel, Connell Foley LLP, 85 Livingston
Avenue, Roseland, New Jersey 07068. Seller shall have the right to extend the
Closing Date for any reason for a period of fifteen (15) days upon written
notice to Buyer, and thereafter for an additional period of thirty (30) days
upon the consent of Buyer's lender. Upon the termination of this Agreement
pursuant to the provisions of this Paragraph 3, this Agreement shall be null and
void, neither party shall have any further rights or obligations under this
Agreement (except for the confidentiality and indemnity obligations of Buyer to
Seller as set forth in Paragraph 16 of this Agreement which shall survive the
cancellation of this Agreement), and all executed counterparts of this Agreement
shall be returned to Seller.

4.       CONDITION OF TITLE.

                  (a) TITLE TO PREMISES. Fee simple title to that portion of the
Premises owned by each party comprising Seller shall be conveyed to Buyer at the
completion of Closing by Seller's bargain and sale deeds with covenants against
grantor's acts in the form of Exhibit F-1 to this Agreement (the "Deeds"),
excluding from Seller's warranty the Permitted Title Exceptions (defined below).
Title to the Personal Property shall be conveyed to Buyer at the completion of
Closing by

                                    2 of 25
<PAGE>

bills of sale in the form of Exhibit F-2 to this Agreement (the "Bills of
Sale"). Title to the Premises shall be such as will be insured as good and
marketable (at Buyer's sole cost and expense) by Escrowee pursuant to the
standard stipulations and conditions of the most current form of ALTA Policy of
Owner's Title Insurance in use in the state in which the Premises is located,
free and clear of all liens and encumbrances except for the Permitted Title
Exceptions. The term "Permitted Title Exceptions" shall mean the Existing
Leases, as defined below, and the additional title exceptions set forth on
Exhibit "C" to this Agreement. Title to the Personal Property shall also be
subject to the Permitted Title Exceptions. Since Buyer has obtained current
title insurance commitments for the Premises ("Buyer's Commitments"), Buyer
agrees that all exceptions to title set forth in the Buyer's Commitments and all
other easements, restrictions, agreements and matters of record as of the
effective date of Buyer's Commitments are deemed to be and constitute Permitted
Title Exceptions (in addition to those set forth on Exhibit C to the Agreement).
Buyer shall provide a copy of Buyer's Commitments to Seller on or before the
date hereof.

                  (b) FAILURE OF TITLE. If on the Closing Date title to the
Premises is not insurable because of a material defect in title arising during
the period from the date hereof until Closing (the "Title Run-Down") and which
Seller cannot cure prior to the Closing Date Buyer may elect, as its sole right
and remedy, either (i) to take such title to the Premises as Seller can convey,
with abatement of the Purchase Price only to the extent of monetary liens of a
definite, fixed and ascertainable amount not in excess of the Purchase Price or
(ii) to terminate this Agreement and receive on written demand to Seller and
Escrowee the return of the Deposit. Upon the return of the Deposit, this
Agreement shall be null and void, neither party shall have any further rights or
obligations under this Agreement (except for the confidentiality and indemnity
obligations of Buyer to Seller as set forth in Paragraph 16 of this Agreement
which shall survive the cancellation of this Agreement), and all executed
counterparts of this Agreement shall be returned to Seller.

                  (c)    TENANT  PURCHASE  RIGHTS.  Except as otherwise set
forth on Schedule 4(c), no tenant of the Premises has purchase rights or rights
of first refusal to purchase the Premises.

        5.       POSSESSION.  Possession of the Premises and the Personal
Property is to be given by Seller to Buyer at the completion of Closing by
delivery of the Deeds and the Bills of Sale.

6.       LEASES; AGREEMENTS.

                  (a) EXISTING LEASES. Seller shall not amend any Existing
Lease, as defined below, in any material respect or execute any new or renewal
lease, license, or other agreement affecting the ownership or operation of all
or any portion of the Premises, nor may Seller execute any new lease or renewal
lease at a net effective rent less than that set forth in the Confidential
Offering Memorandum prepared by CB Richard Ellis, Inc., without the prior
consent of Buyer, which consent shall not be unreasonably withheld, conditioned
or delayed. For purposes of this paragraph, net effective rent will include a
deduction for tenant improvements, leasing commissions, and rollover downtime
prorated over the new lease term. All existing leases listed on Exhibit "D" to
this Agreement, together with lease amendments and new leases entered in
accordance with this Paragraph, are collectively called the "Existing Leases".
Without limiting the effect of any other condition to Closing contained in this
Agreement, the termination of any of the Existing Leases prior to Closing

                                    3 of 25

<PAGE>

by reason of the expiration of its term or by reason of the tenant's default or
exercise of a termination right shall not excuse Buyer from its obligation to
complete Closing and to pay the Purchase Price.

                  (b) EXISTING AGREEMENTS. Seller shall also assign to Buyer at
the completion of Closing, to the extent assignable, Seller's interests under
the existing agreements listed on Exhibit "E" to this Agreement (collectively,
the "Existing Agreements"), which to the best of Seller's knowledge, constitutes
an exclusive list of the Existing Agreements. Seller shall, prior to Closing,
have the right to enter into new service agreements, provided any such agreement
shall be terminable without penalty on not more than thirty (30) days' notice.
Seller shall promptly provide Buyer with a copy of any new service agreement.
All such new service agreements shall also constitute Existing Agreements. The
termination of any of the Existing Agreements prior to Closing by reason of the
expiration of its term or by reason of a default thereunder shall not excuse
Buyer from its obligation to complete Closing and to pay the full Purchase
Price. Seller shall cause its existing management agreement with Keystone Realty
Services, Inc. ("Manager") to be terminated as of Closing.

                  (c) ASSIGNMENT AND ASSUMPTION. At Closing, Seller and Buyer
shall execute and acknowledge an assignment and assumption agreement in the form
of Exhibit "G" to this Agreement (the "Assignment and Assumption Agreement")
pertaining to the Existing Leases and the Existing Agreements.

7.       APPORTIONMENTS.

                  (a) ITEMS TO BE APPORTIONED. Real estate taxes and annual
municipal or special district assessments (on the basis of the actual fiscal
years for which such taxes are assessed), lienable water and sewer rentals, sums
paid to or paid or payable by Seller under the Existing Agreements, prepaid fees
for licenses and permits to remain in effect for Buyer's benefit after closing,
rent and other sums paid to Seller under the Existing Leases and such other
items as are customarily adjusted between sellers and buyers of real estate,
shall be apportioned at Closing pro rata between Buyer and Seller on a per diem
basis as of the Closing Date, with Buyer to receive the economic benefits and
burdens of ownership for the Closing Date.

                  (b) TENANT PASS-THROUGHS. If the apportionment of any
"escalation" payments relating to operating expenses, real estate taxes and
assessments or other additional rent payments under any of the Existing Leases
on account of periods prior to Closing and on account of sums which are
attributable to expenses incurred by the lessor for periods of time prior to
Closing, cannot be precisely determined at the time of Closing, Seller and Buyer
shall reasonably estimate the apportionment of such sums, and such estimated
sums shall be apportioned pro-rata between Buyer and Seller on a per diem basis
as of the Closing Date. A post-Closing adjustment shall be made, if necessary,
between Buyer and Seller for such apportioned items within thirty (30) days
after such sums can be precisely determined.

                  (c) TENANT SECURITY DEPOSITS. At Closing, Seller shall credit
against the Purchase Price the amount of all cash security deposits payable to
tenants then held by or for Seller under the Existing Leases, together with an
amount equal to interest thereon as may be required by law or under the terms of
an Existing Lease, as more particularly set forth on Schedule 7(c) attached
hereto,

                                    4 of 25

<PAGE>

to be paid to any such tenants. At Closing, Seller shall instruct each tenant,
as more particularly set forth in Schedule 7(c), whose security deposit consists
of a letter of credit to cause such letter of credit to be amended to name Buyer
as the beneficiary thereunder.

                  (d)      ARREARAGES.

                           (i)   RENT  ARREARAGES. No prorations shall be made
at Closing with respect to delinquent rents. Any payments received by Buyer
after the Closing Date from a tenant under any of the Existing Leases in arrears
on account of rentals or other sums which are applicable to periods prior to
Closing, shall be apportioned by Buyer upon receipt and the portion thereof
attributable to periods prior to Closing shall immediately be paid by Buyer to
Seller; provided all payments by such tenants after Closing will be deemed as
being applicable, first, as against current month's rental due, then, as against
such arrearages which existed as of Closing. Seller shall be deemed to have
retained all claims existing against tenants for arrearages under any of the
Existing Leases as of Closing.

                           (ii)   ACCOUNTING. Until the earlier to occur of
(A) such time as Seller shall have received in full all sums which are
potentially payable to it on account of any of the Existing Leases as provided
in subparagraph 7(d)(i) or (B) twelve (12) months after Closing, Buyer shall
provide to Seller after Closing a monthly statement of rent received by Buyer
under any of the Existing Leases for those tenants pursuant to which Seller
might be entitled to payments as provided in said subparagraph.

                  (e) LEASING COMMISSIONS; TENANT IMPROVEMENTS. Seller shall pay
or provide Buyer with a credit against the Purchase Price and retain
responsibility for all leasing commissions and tenant improvement allowances set
forth on Schedule 7(e) due on or before the Closing Date in connection with or
arising out of the negotiation, execution and delivery of the Existing Leases.
At Closing, Buyer shall reimburse Seller for all leasing commissions and tenant
costs actually paid or payable by Seller (A) except as set forth below, for
lease transactions entered after the date of this Agreement in accordance with
Paragraph 6(a) of this Agreement and (B) as a result of any renewal or expansion
of Existing Leases which occurs between the date of this Agreement and the
Closing Date which is effectuated pursuant to existing renewal or expansion
options under Existing Leases. Seller shall provide Buyer with invoices and
evidence of Seller's payment of such costs for which Buyer is to reimburse
Seller. Buyer shall timely pay after the Closing Date all leasing commissions
and tenant costs which become due and payable after the Closing Date in
connection with or arising out of the negotiation, execution and delivery of the
Existing Leases . Tenant costs include tenant improvement costs and if the
lease(s) so provides moving costs, design costs incurred by the tenant, lease
buyout costs and tenant inducement costs. Buyer and Seller agree that the
portion of any leasing commission due and payable pursuant to a written
commission agreement by and between Seller and McBride Corporate Real Estate,
Inc. ("McBride") on any lease renewal for any of the Existing Leases as set
forth in Exhibit D in excess of the amount of five percent (5%) (the "Override")
shall be paid by Seller. The parties agree that the amount of any such leasing
commissions up to and including the amount of five percent (5%) shall be paid by
Buyer. (At Closing, Seller shall deliver a letter from McBride confirming the
foregoing regarding the Override.) Seller represents to the best of its
knowledge that: (A) Schedule 7(e) is a complete listing of any leasing
agreements with respect to any extensions, expansions, modifications or renewals
of the

                                    5 of 25

<PAGE>

Existing Leases; and (B) to the extent that Seller derives the benefit of
new rental payments between the date of this Agreement and the Closing Date for
new leases entered into during such period, any leasing commission or tenant
costs due shall be prorated between Seller and Buyer on the basis of the period
of time the respective party derived a benefit from the new lease. In addition,
Buyer will reimburse Seller for the prorated leasing commissions and tenant
costs on Schedule 7(e)(e) for leases executed and approved by Buyer prior to the
Closing Date. The provisions of this Paragraph 7(e) shall survive Closing and
delivery of title to the Premises.

                  (f) NO TAX BILL. If, on the Closing Date, bills for real
estate taxes imposed upon the Premises for the tax fiscal years in which closing
occurs have been issued but shall not have been paid, such taxes shall be paid
at the time of Closing. If such bills shall not have been issued on the Closing
Date, the amount of the taxes shall be reasonably estimated by Seller and Buyer
based upon the then current assessment and anticipated tax rate, and the
portions of such taxes to be borne by Buyer and Seller shall be deposited in
escrow with the Escrowee, to be disbursed by Escrowee promptly after the real
estate tax bills have been issued for the payment of such tax bills. If the
actual taxes are greater than the amounts estimated, Seller and Buyer shall each
pay to the Escrowee, on demand, its pro rata share of such excess.

                  (g) UTILITY READINGS. Seller shall use reasonable efforts to
obtain readings of the water and electric meters on the Premises to a date no
sooner than two (2) business days prior to the Closing Date. At or prior to
Closing, Seller shall pay all charges based upon such meter readings. However,
if after reasonable efforts Seller is unable to obtain readings of any meters
prior to Closing, Closing shall be completed without such readings and upon the
obtaining thereof after closing, Seller shall pay the charges incurred prior to
Closing as reasonably determined by the Seller and Buyer based upon such
readings.

                  (h)    TRANSFER TAXES. Seller shall pay all realty transfer
taxes imposed upon the delivery and/or recording of the Deed(s) and calculated
upon the Purchase Price.

8.       SELLER'S REPRESENTATIONS AND WARRANTIES.

                  (a)      Seller represents and warrants to Buyer as follows:

                           (i)      ORGANIZATION. Seller is a general
partnership, duly organized and validly existing under the laws of the State of
New Jersey and has all requisite partnership power and authority to carry on its
business as now conducted.

                           (ii)     AUTHORIZATION. Seller has the requisite
partnership, corporate and/or limited liability power and authority to enter
into and perform this Agreement, and Seller has duly authorized the execution of
this Agreement.

                           (iii)    NO CONDEMNATION. To Seller's knowledge,
there are no existing or pending condemnation proceedings or deeds in lieu of
condemnation affecting the Premises, nor, to Seller's knowledge, have any such
condemnation proceedings been threatened.

                                    6 of 25

<PAGE>

                           (iv)     NO NOTICES. Except as set forth in
Schedule 8(a)(iv) to this Agreement, Seller has not received any written notice
from any public authority asserting the existence of any presently uncorrected
violation of any ordinance, public regulation or statute with respect to the
Premises ("Notice of Violation"). In the event that Seller receives any such
Notice of Violation prior to the Closing Date, Seller's obligation to remedy
such Notice of Violation should not exceed $100,000.00 singularly or in the
aggregate. In the event the cost of remediation shall exceed $100,000.00, and
the Seller elects not to cure the violations or pay such additional amount to
remediate the violations, Buyer shall have the option of either (1) taking a
credit of $100,000.00 from the Seller and proceeding to closing, whereupon Buyer
shall be solely responsible for remedying the violations, or (2) Buyer shall
have the right to terminate this Agreement, whereupon the Deposit plus interest
shall be returned to the Buyer and this Agreement shall be null and void. Buyer
represents and warrants that Buyer shall not request or encourage an
inspection(s) of the Premises by any federal, state or municipal official(s)
having jurisdiction over the Premises in connection with Buyer's due diligence
with respect to a Notice of Violation(s).

                           (v)      NO PROCEEDINGS. Except as set forth on
Schedule 8(a)(v) to this Agreement, Seller has received no written notice of any
pending actions, suits or proceedings against Seller or the Premises which are
not covered by Seller's insurance nor, to Seller's knowledge, is there any
action, suit or proceeding against Seller or the Premises threatened which would
materially and adversely affect the Premises or Seller's ability to perform its
obligations under this Agreement.

                           (vi)     EXISTING LEASES. The list of Existing Leases
attached to this Agreement as Exhibit "D" is true, correct and complete in all
material respects. To Seller's knowledge, all of the Existing Leases listed on
Exhibit "D" are, except as otherwise noted thereon, in full force and effect and
Seller has received no notice of default from any of the tenants thereunder
which remains uncured. To Seller's knowledge, except as otherwise noted on
Exhibit "D", Seller and none of the tenants are in default under the respective
Existing Lease (except for rental obligations for the current month) in any
material respect. Except as set forth on Exhibit "D", Seller has received no
prepayments of rent under any Existing Lease. Except as set forth on Exhibit
"D", all tenant allowances payable to the date of this Agreement have been paid
in full, and all tenant improvement obligations of the Landlord under the
Existing Leases to be performed to the date of this Agreement have been
materially completed. The copies of the Existing Leases previously delivered by
Seller to Buyer or made available by Seller to Buyer for review are true and
complete copies in all material respects of such Existing Leases and the same
have not been further amended, modified or supplemented.

                           (vii)    EXISTING AGREEMENTS. Exhibit "E" is a true,
correct and complete list of all Existing Agreements to which Seller is a party
or by which Seller is bound for the provision of services to or management of
the Premises. Seller has delivered to Buyer true and correct copies of all
Existing Agreements. There are no service agreements which Seller has executed
affecting the Premises other than those listed on Exhibit "E".

                          (viii)   TAX APPEALS. Buyer shall have the right to
file real estate tax appeals for the Premises, between the date of this
Agreement and the Closing Date upon Seller's prior consent which shall not be
unreasonably withheld or delayed. If any tax appeals are currently

                                    7 of 25

<PAGE>


pending with respect to the Premises, Seller shall cause Buyer's attorney to be
substituted as counsel and any awards shall be adjusted according to the
respective party's period of ownership after any expenses have been paid.

                          (ix)   SECURITY DEPOSITS. Seller agrees not to apply
any tenant security deposits to rent or other amounts due for any tenants in
possession as of the Closing Date.

                  (b) All references in this Paragraph 8 or elsewhere in this
Agreement to "Seller's knowledge" or "Seller's actual knowledge" shall refer
solely to the actual knowledge (without independent investigation) of Stephen J.
Butte an officer of Keystone Property Trust, and shall not be construed to refer
to the knowledge of any other employee, officer, director, shareholder or agent
of Seller or any affiliate of Seller, and shall not include imputed or
constructive knowledge.

             9.   BUYER'S REPRESENTATIONS AND WARRANTIES. Buyer represents and
warrants to Seller as follows:

                  (a)  ORGANIZATION. Buyer is a limited liability company duly
organized and validly existing under the laws of the State of New Jersey and has
all requisite power and authority to carry on its business as now conducted.

                  (b)  AUTHORIZATION. Buyer has the requisite power and
authority to enter into and perform this Agreement and Buyer has duly authorized
the execution of this Agreement.

                  (c)  Buyer shall diligently pursue all financing in connection
with the acquisition of the Premises and shall promptly file or cause to be
filed all necessary application(s) and third party reports.

                  (d) Within seven (7) days of Seller's request, Buyer shall
submit to Seller an allocation of the Purchase Price for each of the properties
comprising the Premises.

             10.  CONDITIONS TO CLOSING.


                  (a)   BUYER'S CONDITIONS. Buyer shall not be obligated to
close under this Agreement unless each of the following conditions shall be
satisfied on the Closing Date:

                           (i)      TITLE POLICY. The Title Run-Down for the
Premises prepared by Escrowee shall not contain any material defects in title
occurring after the date hereof until Closing not otherwise curable by Seller
prior to the Closing Date.

                           (ii)     ACCURACY OF REPRESENTATIONS. The
representations and warranties made by Seller in this Agreement shall be true
and correct as of the Closing Date in all material respects.

                           (iii)    TENANT ESTOPPEL CERTIFICATES. Seller shall
have obtained and delivered to Buyer by Closing Tenant Estoppel Certificates (as
defined below) for tenants constituting 75% of

                                    8 of 25

<PAGE>


the total aggregate net rentable square footage for all of the Premises. The
term "Tenant Estoppel Certificate" shall refer to a written statement in
substantially the form of the Tenant Estoppel Certificate set forth on Exhibit
"H-1" to this Agreement or in the form which any tenant is required to give
under its lease. Buyer agrees not to object to any non-material qualifications
or modifications, including any "knowledge" qualification as to defaults which a
tenant may make to the form of Tenant Estoppel Certificate. If any tenant has a
valid claim which would entitle it to set-off the amount of the claim against
rent due under such tenant's lease and the amount of such claim is
ascertainable, Seller shall have the right, at its sole option, to give Buyer a
credit against the Purchase Price in the amount of the claim and, in such event,
Buyer shall, subject to the provisions of this Agreement, complete Closing
subject to such claim and shall automatically be deemed to release and indemnify
Seller from and against all liability in connection therewith. With respect to
any Tenants from whom the Seller does not obtain Tenant Estoppel Certificates,
Seller shall deliver a landlord estoppel certificate representing that there are
no rent concessions. The Seller's landlord estoppel certificate shall survive
through the end of the respective lease term(s).

                  (b)      SELLER'S CONDITIONS. Seller shall not be obligated to
complete Closing under this Agreement unless each of the following conditions
shall be satisfied on the Closing Date:

                           (i)      BUYER'S PERFORMANCE. Buyer shall have paid
the Purchase Price and shall have complied with and performed in all material
respects all of its other obligations under this Agreement.

                           (ii)     ISRA. Seller shall have obtained Evidence of
ISRA Compliance (as such term is defined in Paragraph 22 of this Agreement).

         11.     SELLER'S DELIVERIES AT CLOSING.

                  (a)      SELLER'S DELIVERIES. On the Closing Date, each party
comprising Seller shall deliver or cause to be delivered to Escrowee for
delivery to Buyer upon the completion of Closing the following:

                           (i)      DEEDS.  The Deeds and any necessary transfer
 tax documents.

                           (ii)     BILLS OF SALE.  The Bills of Sale.

                           (iii)    ASSIGNMENT AND ASSUMPTION AGREEMENTS. The
Assignment and Assumption Agreements.

                           (iv)     AUTHORITY DOCUMENTS. A resolution
evidencing Seller's authorization of the transaction contemplated by this
Agreement and an incumbency certificate to evidence the capacity of the
signatories for Seller.

                           (v)      FIRPTA CERTIFICATIONS AND TITLE AFFIDAVITS.
The Certification in the form attached to this Agreement as Exhibit "I" with
respect to the Foreign Investment in Real Property Tax Act (Internal Revenue
Code Section 1445, as amended, and the regulations issued

                                    9 of 25

<PAGE>

thereunder) and a title affidavit in favor of Escrowee in the form of Exhibit
"J" to this Agreement (which affidavit in no event will expand Seller's warranty
contained in the Deed).

                           (vi)     KEYS.  All keys, codes and other security
devices for the Premises.

                           (vii)    BOOKS AND RECORDS. Copies (to the extent in
Seller's possession) of all books and records for the orderly transition of
operation of the Premises.

                           (viii)   ORIGINAL DOCUMENTS. The originals (to the
extent in Seller's possession) of all Existing Leases, Existing Agreements,
tenant files and Intangible Personal Property.

                           (ix)     SELLER'S CLOSING CERTIFICATE. Seller's
Closing Certificate in the form of Exhibit "K" to this Agreement.

                           (x)      CLOSING STATEMENT. An executed original
closing statement setting forth the Purchase Price and prorations between the
parties.

                           (xi)     OTHER DOCUMENTS. Any other documents which
Seller is obligated to deliver to Buyer pursuant to this Agreement.

                  (b)      BUYER'S DELIVERIES. On the Closing Date, Buyer will
deliver to Escrowee for delivery to Seller upon the completion of Closing the
following:

                           (i)      ASSIGNMENT AND ASSUMPTION AGREEMENTS. The
Assignment and Assumption Agreements.

                           (ii)     AUTHORITY  DOCUMENTS. A corporate resolution
or partnership resolution executed by the general partners, as the case may be,
and an incumbency certificate to evidence the capacity of the signatory for
Buyer.

                           (iii)    PURCHASE PRICE. That portion of the Purchase
Price payable at Closing.

                           (iv)     CLOSING STATEMENT. An executed original
closing statement setting forth the Purchase Price and prorations between the
parties.

                           (v)      OTHER DOCUMENTS. Any other documents which
Buyer is obligated to deliver to Seller pursuant to this Agreement.

12.      DEFAULT.

                  (a) BUYER DEFAULT. If Buyer defaults under this Agreement at
or prior to the Closing Date by failing to complete the Closing in accordance
with the terms of this Agreement or fails to perform or observe any of the
covenants or agreements to be performed by Buyer hereunder, then on the earlier
of the Closing Date or the date of such default, the Deposit shall be paid to
Seller

                                    10 of 25

<PAGE>


by Escrowee. The Deposit shall be retained by Seller as liquidated damages and
not as a penalty. The retention of the Deposit shall be Seller's sole and
exclusive remedy in the event of Buyer's failure to complete Closing, and Seller
in such event waives any right, unless Closing is completed, to recover the
balance of the Purchase Price. Seller and Buyer agree that the actual damages to
Seller in the event of such breach are impractical to ascertain as of the date
of this Agreement and the amount of the Deposit is a reasonable estimate
thereof. If Seller shall retain the Deposit as liquidated damages, this
Agreement shall be and become null and void and all copies will be surrendered
to Seller; provided, nothing in this Paragraph shall limit Seller's rights
against Buyer by reason of any indemnity or confidentiality obligations of Buyer
to Seller set forth in this Agreement all of which shall survive the termination
of this Agreement.

                  (b) SELLER DEFAULT. If Seller defaults under this Agreement by
failing to complete Closing in accordance with the terms of this Agreement, then
Buyer shall be entitled, as Buyer's sole and exclusive remedy, to either (i)
institute an action for specific performance of this Agreement; or (ii) seek
reimbursement of the Deposit.

         13.      NOTICES; COMPUTATION OF PERIODS.

                  (a) NOTICES. All notices given by either party to the other
shall be in writing and shall be sent either (i) by United States Postal Service
registered or certified mail, postage prepaid, return receipt requested, (ii) by
nationally recognized overnight courier service for next business day delivery,
addressed to the other party at the following addresses listed below or (iii)
via telecopier or facsimile transmission to the facsimile numbers listed below,
provided, however, that if such communication is given via telecopier or
facsimile transmission, an original counterpart of such communication shall
concurrently be sent in the manner specified in clause (ii) above. Addresses and
facsimile numbers of the parties are as follows:

                  As to Seller:
                  200 Four Falls Corporate Center
                  Suite 208
                  West Conshohocken, PA 19428
                  Attention:  Stephen J. Butte
                  Fax:  (484) 530-0131

                  with copies at the same time to:

                  Connell Foley LLP
                  85 Livingston Avenue
                  Roseland, New Jersey 07068
                  Attention:  John D.Cromie, Esq.
                  Fax:  (973) 535-9217

                                    11 of 25

<PAGE>

                  As to Buyer:

                  Fawn Realty L.L.C..
                  26 Columbia Turnpike
                  Florham Park, New Jersey 07932
                  Attention:  Charles Kushner
                              Richard Stadtmauer
                  Fax:     (973) 822-8481

                  with a copy at the same time to:

                  Brach Eichler Rosenberg Bernstein Hammer & Gladstone
                  101 Eisenhower Parkway
                  Roseland, New Jersey 07068
                  Attention:  Alan Hammer, Esq.
                  Fax:  (973) 228-7852

                  As to Escrowee:

                  Chicago Title Insurance Company
                  c/o Professional Abstract & Title Agency, Inc.
                  520 Westfield Avenue
                  Elizabeth, New Jersey 07208
                  Attention:  Drew Swider

or to such other address as the respective parties may hereafter designate by
notice in writing in the manner specified above. Any notice may be given on
behalf of any party by its counsel. Notices given in the manner aforesaid shall
be deemed sufficiently served or given for all purposes under this Agreement
upon the earliest of (i) actual receipt or refusal by the addressee, or (ii) the
date such notices, demands or requests shall be deposited in any Post Office, or
branch Post Office regularly maintained by the United States Government or
delivered to the overnight courier service.

                  (b) COMPUTATION OF PERIODS. If the final day of any period of
time in any provision of this Agreement falls upon a Saturday, Sunday or a
holiday observed by federally insured banks in the Commonwealth of Pennsylvania
or the State in which the Premises is located or by the United States Postal
Service, then, the time of such period shall be extended to the next day which
is not a Saturday, Sunday or holiday. Unless otherwise specified, in computing
any period of time described in this Agreement, the day of the act or event
after which the designated period of time begins to run is not to be included
and the last day of the period is so computed is to be included, unless such
last day is a Saturday, Sunday or holiday in which event the period shall run
until the end of the next day which is neither a Saturday, Sunday or holiday.

14.      FIRE OR OTHER CASUALTY.

                                    12 of 25

<PAGE>


                  (a)  CASUALTY INSURANCE. Seller agrees to maintain in effect
until the Closing Date the fire and extended coverage insurance policies now in
effect for the Premises.

                  (b) CASUALTY DAMAGE. Subject to subparagraph (c) below, the
obligations of the parties to complete Closing under this Agreement shall in no
way be voided or impaired if the Premises or Personal Property, or any part
thereof, shall be damaged or destroyed by fire or other casualty between the
date of this Agreement and the Closing Date. If any such damage or destruction
occurs after the date of this Agreement: (i) Seller shall provide Buyer with
notice thereof, (ii) the cash proceeds of all fire and extended coverage
insurance policies attributable to the Premises or the Personal Property
received by Seller or the holder of any mortgage encumbering the Premises prior
to the Closing Date and not used for the repair of the Premises and the Personal
Property (and Buyer hereby authorizes Seller to use the proceeds for such
purpose) shall be applied on account of the cash portion of the Purchase Price
payable at Closing and (iii) all unpaid claims of Seller under such insurance
policies attributable to the Premises and Personal Property shall be assigned by
Seller to Buyer at the Closing.

                  (c) RIGHT OF TERMINATION. Notwithstanding any of the preceding
provisions of this Paragraph 14, if the cost to repair damage caused by fire or
other casualty to the Premises exceeds Six Million Dollars ($6,000,000.00),
Buyer shall have the right to terminate this Agreement by written notice to
Seller. Upon such termination, the Deposit shall be returned by Escrowee to
Buyer and neither party shall have any further rights or obligations under this
Agreement (except for the indemnity and confidentiality obligations of Buyer to
Seller set forth in Paragraph 16 of this Agreement which shall survive the
termination of this Agreement). If Buyer desires to terminate this Agreement
pursuant to this subparagraph (c), Buyer shall give a written notice of
termination to Seller within ten (10) business days after Seller's notice to
Buyer of the occurrence of the casualty. If Seller's notice pursuant to
Paragraph 14(b)(i) is given to Buyer less than ten (10) business days prior to
Closing, at Buyer's option Closing may be postponed to a date not earlier than
ten (10) business days or later than thirty (30) days after Buyer's receipt of
such notice. Notwithstanding anything to the contrary, in the event the Lender
applies substantially all of the insurance proceeds in connection with a fire or
other casualty to pay down the debt under the Existing Loan, the Buyer shall
have the right to terminate this Agreement.

15.      ASSIGNABILITY.

                           (a)    LIMITED ASSIGNMENT. Subject to the further
limitations in subparagraph (b) below, this Agreement, and all, but not part, of
Buyer's rights under this Agreement, may be assigned by Buyer, without the prior
written consent of Seller, to an entity which is qualified to do business in the
State of New Jersey and which is managed or controlled by Charles Kushner;
provided, however, that such assignment shall not release or relieve Buyer of
and from any liability or obligation under this Agreement, and Buyer shall
continue to be primarily liable to Seller under this Agreement. No such
assignment shall be effective, however, unless and until Buyer shall have
furnished to Seller both an executed copy of the assignment plus a written
assumption agreement, in form satisfactory to Seller, by the assignee to assume,
perform and be responsible, jointly and severally with the Buyer named herein,
for the performance of all of the obligations of Buyer under this Agreement and
to pay all additional transfer or documentary taxes imposed as a

                                    13 of 25

<PAGE>


result of such assignment, and which contains a representation by the assignee
that all of the representations and warranties made by Buyer in this Agreement
are true and correct with respect to the assignee as of the date of the
assumption agreement. Seller shall have the right to rely in good faith on the
genuineness and validity of the notice from Buyer of an assignment and to convey
the Premises to the assignee without liability to Buyer or any other person.
Buyer shall indemnify and save Seller harmless from and against any such
liability in connection with such conveyance to the assignee.

                           (b)  SUCCESSORS AND ASSIGNS. Except as provided in
subparagraph 15(a), Buyer may not assign or suffer an assignment of this
Agreement and its rights under this Agreement, without the prior written consent
of Seller, which consent Seller may deny in its sole and absolute discretion.
Subject to the foregoing limitations, this Agreement shall extend to, and shall
bind, the respective heirs, executors, personal representatives, successors and
assigns of Seller and Buyer.

16.      INSPECTION PERIOD.

                  (a) RIGHT TO INSPECT. Buyer, and Buyer's agents and
representatives, have completed their inspection of the Premises and Buyer is
satisfied with the condition of the Premises. Seller represents and warrants, to
the best of its knowledge and without independent investigation, that since
March 17, 2000 (i) there has been no material change in the condition of the
Premises, ordinary wear and tear excepted, and (ii) it has not received any
correspondence from any of the tenants at the Premises indicating the presence
of any material defect in the condition of the Premises, ordinary wear and tear
excepted. The costs of all inspections and examinations so performed shall be
borne by Buyer.

                  (b) NO LIENS PERMITTED. Nothing contained in this Agreement
shall be deemed or construed in any way as constituting the consent or request
of Seller, express or implied by inference or otherwise, to any party for the
performance of any labor or the furnishing of any materials to the Premises or
any part thereof, nor as giving Buyer any right, power or authority to contract
for or permit the rendering of any services or the furnishing of any materials
that would give rise to the filing of any liens against the Premises or any part
thereof.

                  (c)      [Intentionally deleted.]

                  (d)      DELIVERIES. Buyer acknowledges that Seller has made
available for inspection by Buyer the following:

                           (i)      copies of plans and specifications for the
Premises, to the extent currently in Seller's possession;

                           (ii)     the current books and records (excluding,
however, tax records, internal memoranda, financial projections, appraisals and
projected budgets) customarily prepared by or at Seller's request with respect
to the Premises, including, without limitation, to the extent so prepared, all
ledgers, records of income, expense, capital expenditures, utility bills and the
most recent property tax bill;


                                    14 of 25

<PAGE>

                           (iii)    copies of all Existing Agreements currently
in force with respect to the Premises;

                           (iv)     copies of all Existing Leases currently in
force with respect to the Premises;

                           (v)      copies of environmental assessment reports
 listed on Schedule 16(d)(v);

                           (vi)     copies of engineering reports,  title
documents and surveys for the Premises to the extent currently in Seller's
possession;

                           (vii)    copies of all service, maintenance and other
contracts currently in force with respect to the Premises to the extent
currently in Seller's possession;

                           (viii)   copies of all certificates of occupancy
issued with respect to the Premises to the extent currently in Seller's
possession;

                           (ix)     copies of real estate tax bills for the
Premises for the most recent tax year.

                  (e) NO WARRANTY. NOTWITHSTANDING THE PROVISIONS OF
SUBPARAGRAPH 16(d), BUYER ACKNOWLEDGES THAT SOME OF THE MATERIALS DELIVERED BY
SELLER HAVE BEEN PREPARED BY PARTIES OTHER THAN SELLER. EXCEPT AS SPECIFICALLY
SET FORTH IN THIS AGREEMENT, SELLER MAKES NO REPRESENTATION OR WARRANTY
WHATSOEVER, EXPRESS OR IMPLIED, AS TO THE COMPLETENESS, CONTENT OR ACCURACY OF
THE DELIVERED MATERIALS WHICH WERE NOT PREPARED BY SELLER.

                  (f) Buyer shall hold as confidential all information
concerning Seller or the Premises obtained by Buyer in connection with the
transactions contemplated by this Agreement. Buyer shall not, prior to
completion of Closing, release any such information relating to Seller or the
Premises without Seller's prior written consent, except pursuant to court order
or as may otherwise be required by law. Seller hereby consents to Buyer's
disclosure of information relating to Seller or the Premises to Buyer's
prospective mortgage lenders and investors, consultants, officers, directors and
attorneys.

                  (g) INDEMNIFICATION. Buyer shall (i) restore any damage to the
Premises or any adjacent property arising from the exercise by Buyer of its
rights under subparagraph 16(a) and (ii) indemnify, defend and save Seller and,
as the case may be, its partners and its and their trustees, shareholders,
directors, officers, members, employees, and agents (each, an "Indemnified
Party") harmless from and against all claims, costs, liabilities and expenses
(including without limitation attorneys' fees and court costs) incurred by any
Indemnified Party and arising from the exercise by Buyer of its rights under
subparagraph 16(a) or from the breach by Buyer of its obligations under


                                    15 of 25

<PAGE>


subparagraph 16(f). Notwithstanding anything contained in this Agreement, in no
event shall Seller's remedies or right to collect damages under this
subparagraph 16(g) be limited to the Deposit or the amount thereof, and in such
event Seller may pursue all rights and remedies available to Seller at law or
equity.

17.      CONDEMNATION.

                  (a) IMMATERIAL TAKING. If any part of the Premises shall be
taken by exercise of the power of eminent domain after the date of this
Agreement which does not materially interfere with the use of the Premises for
the purposes for which it is currently intended to be used, this Agreement shall
continue in full force and effect and there shall be no abatement of the
Purchase Price. Seller shall be relieved, however, of its duty to convey title
to the portion so taken, but Seller shall, on the Closing Date, assign to Buyer
all rights and claims to any awards arising therefrom as well as any money
theretofore received by Seller on account thereof, net of any expenses to
Seller, including attorneys' fees of collecting the same. Seller shall promptly
furnish Buyer with a copy of the declaration of taking property after Seller's
receipt thereof.

                  (b) MATERIAL TAKING. If any such taking of a portion of the
Premises materially interferes with the use of the Premises for the purposes for
which it is currently intended to be used, either Seller or Buyer may terminate
this Agreement by written notice to the other party. Upon the giving of such
termination notice, this Agreement shall become null and void except for the
indemnity obligations of Buyer to Seller set forth in this Agreement which will
survive termination of this Agreement, and all executed counterparts of this
Agreement shall be returned to Seller. If this Agreement is not so terminated
pursuant to this subparagraph (b), the provisions of subparagraph (a) above
shall govern.

18.      BROKERS.

                  (a) Buyer represents and warrants to Seller that Buyer has
dealt with no broker or other intermediary in connection with this transaction
or the Premises other than Kislak Realty (the "Buyer's Disclosed Broker"). Buyer
shall pay Buyer's Disclosed Broker a brokerage commission pursuant to a separate
agreement. If any broker or other intermediary other than the Buyer's Disclosed
Broker claims to have dealt with Buyer in connection with this transaction or
the Premises, to have introduced the Premises to Buyer for sale, or to have been
the inducing cause to the sale, Buyer shall indemnify, defend and save Seller
harmless of and from any claim for commission or compensation by such broker or
other intermediary.

                  (b) Seller represents and warrants to Buyer that Seller has
dealt with no broker in connection with this transaction or the Premises other
than CB Richard Ellis, Inc. (the "Seller's Disclosed Broker"). Seller shall pay
Seller's Disclosed Broker a brokerage commission pursuant to a separate
agreement. If any broker or other intermediary other than the Seller's Disclosed
Broker claims to have dealt with Seller in connection with this transaction or
the Premises, or to have been the inducing cause to the sale, Seller shall
indemnify, defend and save Buyer harmless of and from any claim for commission
or compensation by such broker or other intermediary.

                                    16 of 25

<PAGE>

19.      CONDITION OF PREMISES.

                  (a) NO WARRANTIES. THE ENTIRE AGREEMENT BETWEEN THE SELLER AND
BUYER WITH RESPECT TO THE PREMISES AND THE PERSONAL PROPERTY AND THE SALE
THEREOF IS EXPRESSLY SET FORTH IN THIS AGREEMENT. THE PARTIES ARE NOT BOUND BY
ANY AGREEMENTS, UNDERSTANDINGS, PROVISIONS, CONDITIONS, REPRESENTATIONS OR
WARRANTIES (WHETHER WRITTEN OR ORAL AND WHETHER MADE BY SELLER OR ANY AGENT,
EMPLOYEE OR PRINCIPAL OF SELLER OR ANY OTHER PARTY) OTHER THAN AS ARE EXPRESSLY
SET FORTH AND STIPULATED IN THIS AGREEMENT. WITHOUT IN ANY MANNER LIMITING THE
GENERALITY OF THE FOREGOING, BUYER ACKNOWLEDGES THAT IT AND ITS REPRESENTATIVES
HAVE FULLY INSPECTED THE PREMISES, THE PERSONAL PROPERTY, THE ASSIGNED EXISTING
AGREEMENTS, OR WILL BE PROVIDED WITH AN ADEQUATE OPPORTUNITY TO DO SO, ARE OR
WILL BE FULLY FAMILIAR WITH THE FINANCIAL AND PHYSICAL (INCLUDING WITHOUT
LIMITATION, ENVIRONMENTAL) CONDITION THEREOF, AND THAT THE PREMISES, THE
PERSONAL PROPERTY, THE ASSIGNED EXISTING AGREEMENTS HAVE BEEN PURCHASED BY BUYER
IN AN "AS IS" AND "WHERE IS" CONDITION AND WITH ALL EXISTING DEFECTS AS A RESULT
OF SUCH INSPECTIONS AND INVESTIGATIONS AND NOT IN RELIANCE ON ANY AGREEMENT,
UNDERSTANDING, CONDITION, WARRANTY (INCLUDING, WITHOUT LIMITATION, WARRANTIES OF
HABITABILITY, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE) OR
REPRESENTATION MADE BY SELLER OR ANY AGENT, EMPLOYEE OR PRINCIPAL OF SELLER OR
ANY OTHER PARTY (EXCEPT AS EXPRESSLY ELSEWHERE PROVIDED IN THIS AGREEMENT) AS TO
THE FINANCIAL OR PHYSICAL (INCLUDING, WITHOUT LIMITATION, ENVIRONMENTAL)
CONDITION OF THE PREMISES OR THE PERSONAL PROPERTY OR THE AREAS SURROUNDING THE
PREMISES, AS TO ANY MATTER, INCLUDING WITHOUT LIMITATION AS TO ANY PERMITTED USE
THEREOF, THE ZONING CLASSIFICATION THEREOF OR COMPLIANCE THEREOF WITH FEDERAL,
STATE OR LOCAL LAWS, AS TO THE INCOME OR EXPENSE IN CONNECTION THEREWITH, OR AS
TO ANY OTHER MATTER IN CONNECTION THEREWITH. BUYER ACKNOWLEDGES THAT NEITHER
SELLER, NOR ANY AGENT OR EMPLOYEE OF SELLER, NOR ANY OTHER PARTY ACTING ON
BEHALF OF SELLER HAS MADE OR SHALL BE DEEMED TO HAVE MADE ANY SUCH AGREEMENT,
CONDITION, REPRESENTATION OR WARRANTY EITHER EXPRESSED OR IMPLIED. THIS
PARAGRAPH SHALL SURVIVE CLOSING, AND SHALL BE DEEMED INCORPORATED BY REFERENCE
AND MADE A PART OF ALL DOCUMENTS DELIVERED BY SELLER TO BUYER IN CONNECTION WITH
THE SALE OF THE PREMISES AND THE PERSONAL PROPERTY.

                  (b) CONDITION OF DELIVERY. Seller has no obligation to deliver
the Premises in a "broom clean" condition if it is currently not in broom clean
condition, and at Closing Seller may leave in the Premises all items of personal
property and equipment, partitions and debris as are now presently therein;
provided, however, that in cases where an Existing Lease has terminated or
expired, as of the Closing Date, Seller shall deliver the subject premises in
good clean condition, ordinary wear and tear excepted.

                                    17 of 25

<PAGE>

                  (c) SELLER REPAIRS. Between the date of the execution of this
Agreement and the Closing Date, Seller shall perform such ordinary repairs to
the Premises and the Personal Property as Seller has customarily previously
performed to maintain them in substantially the same condition as they are as of
the end of the Inspection Period, as said condition shall be changed by wear and
tear and damage by fire or other casualty.

                  (d) RELEASE. WITHOUT LIMITING THE PROVISIONS OF SUBPARAGRAPH
19 (a) ABOVE AND NOTWITHSTANDING ANYTHING TO THE CONTRARY CONTAINED IN THIS
AGREEMENT, BUYER HEREBY RELEASES SELLER AND (AS THE CASE MAY BE) SELLER'S
OFFICERS, DIRECTORS, SHAREHOLDERS, TRUSTEES, PARTNERS, EMPLOYEES, MANAGERS,
ATTORNEYS AND AGENTS FROM ANY AND ALL CLAIMS, DEMANDS, CAUSES OF ACTIONS,
LOSSES, DAMAGES, LIABILITIES, COSTS AND EXPENSES (INCLUDING ATTORNEYS' FEES
WHETHER SUIT IS INSTITUTED OR NOT) WHETHER KNOWN ( PROVIDED THE SAME IF ACTUALLY
KNOWN BY SELLER ARE DISCLOSED BY SELLER) OR UNKNOWN, LIQUIDATED OR CONTINGENT
(COLLECTIVELY THE "CLAIMS") ARISING FROM OR RELATING TO (i) ANY DEFECTS, ERRORS
OR OMISSIONS IN THE DESIGN OR CONSTRUCTION OF THE PREMISES WHETHER THE SAME ARE
THE RESULT OF NEGLIGENCE OR OTHERWISE, OR (ii) ANY OTHER CONDITIONS, INCLUDING
ENVIRONMENTAL AND OTHER PHYSICAL CONDITIONS, AFFECTING THE PREMISES WHETHER THE
SAME ARE A RESULT OF NEGLIGENCE OR OTHERWISE. THE RELEASE SET FORTH IN THIS
SECTION SPECIFICALLY INCLUDES, WITHOUT LIMITATION, ANY CLAIMS UNDER ANY
ENVIRONMENTAL LAWS OF THE UNITED STATES, THE STATE IN WHICH THE PREMISES IS
LOCATED OR ANY POLITICAL SUBDIVISION THEREOF OR UNDER THE AMERICANS WITH
DISABILITIES ACT OF 1990, AS ANY OF THOSE LAWS MAY BE AMENDED FROM TIME TO TIME
AND ANY REGULATIONS, ORDERS, RULES OF PROCEDURE OR GUIDELINES PROMULGATED IN
CONNECTION WITH SUCH LAWS, REGARDLESS OF WHETHER THEY ARE IN EXISTENCE ON THE
DATE OF THIS AGREEMENT. BUYER ACKNOWLEDGES THAT BUYER HAS BEEN REPRESENTED BY
INDEPENDENT LEGAL COUNSEL OF BUYER'S SELECTION AND BUYER IS GRANTING THIS
RELEASE OF ITS OWN VOLITION AND AFTER CONSULTATION WITH BUYER'S COUNSEL.

                  (e) SELLER REPORTS. Buyer acknowledges that Seller makes no
warranties or representations regarding the adequacy, accuracy or completeness
of environmental and engineering reports delivered to Buyer by Seller
(collectively the "Reports") or other documents relating to the Reports, and
Buyer shall have no claim against Seller based upon the Reports or such other
documents relating to the Reports. Buyer further acknowledges that Buyer has had
full opportunity to perform such environmental and engineering investigations as
Buyer deems appropriate prior to entering into this Agreement or shall have such
opportunity during the Inspection Period, and Buyer obtained or shall obtain its
own environmental and engineering reports of the Premises. At Seller's request,
Buyer agrees to provide Seller with copies of all environmental and engineering
reports and appraisals ordered by Buyer with respect to the Premises.

                                    18 of 25

<PAGE>


                  (f) EFFECT OF DISCLAIMERS. Buyer acknowledges and agrees that
the Purchase Price has been negotiated to take into account that the Premises
and Personal Property are being sold subject to the provisions of Section d of
this Paragraph 19 and that Seller would have charged a higher purchase price if
the provisions in this Paragraph 19 were not agreed upon by Buyer.

20.      SURVIVAL OF PROVISIONS.

                  (a) Except as otherwise provided in this Paragraph 20,
acceptance by Buyer of the Deeds at Closing shall constitute an acknowledgment
by Buyer of full performance by Seller of all of Seller's obligations under this
Agreement and none of Seller's representations and warranties contained in this
Agreement shall survive closing.

                  (b) (i) Notwithstanding any provision to the contrary set
forth in this Agreement, the agreements and obligations of Seller under
Paragraphs 7 and 18 shall survive Closing, and the warranties and
representations of Seller set forth in subparagraph 8(a) (the "Surviving
Warranties") shall survive Closing under this Agreement for a period of six (6)
months, and Seller's representations set forth on the Schedules and Exhibits
attached to this Agreement shall survive the Closing of title for a period of
three (3) months, provided however, the parties acknowledge that the Schedules
and Exhibits attached hereto are incomplete and the parties shall endeavor to
complete the Schedules and Exhibits within fourteen (14) days of this Agreement.
Notwithstanding the foregoing, the representations and warranties of Seller
contained in subparagraph 8(a)(vi) with respect to any Existing Lease shall not
survive the delivery to Buyer of a Tenant Estoppel Certificate to the extent
such Tenant Estoppel Certificate confirms matters represented and warranted by
Seller with respect to such Existing Lease, and the representations and
warranties of Seller contained in subparagraph 8(a)(viii) shall not survive
Closing to the extent the Lender confirms for Buyer matters represented and
warranted by Seller in subparagraph 8(a)(viii). For example, if a Tenant
Estoppel Certificate is received from a tenant and such certificate confirms
some but not all of Seller's representations and warranties with respect to such
Existing Lease contained in Paragraph 8(a)(vi), the representations and
warranties of Seller with respect to the matters so confirmed shall not survive
Closing and the representations and warranties of Seller with respect to the
matters not so confirmed shall survive Closing as provided above.

                           (ii)     If Buyer determines that any of the
Surviving Warranties are inaccurate in any material respect prior to the Closing
Date, Buyer's sole right and remedy shall be to terminate this Agreement by
giving to Seller written notice of such termination on or prior to the Closing
Date. If Buyer fails to timely give such written termination notice to Seller,
Buyer shall be deemed to have waived any right or remedy (including, without
limitation, any right under this Agreement to terminate this Agreement) against
Seller by reason of the inaccuracy of such warranty. If Buyer terminates this
Agreement pursuant to this Paragraph, Buyer shall be entitled to the return of
the Deposit, and upon the return of the Deposit to Buyer, neither Buyer nor
Seller shall have any further rights nor obligations under this Agreement
(except for the indemnity and confidentiality obligations of Buyer to Seller set
forth in Paragraph 16 of this Agreement which will survive such termination).

                           (iii)    Seller shall have no liability to Buyer by
reason of a breach or default of any of the Surviving Warranties unless Buyer
shall have given to Seller written notice ("Warranty

                                    19 of 25

<PAGE>


Notice") of such breach or default within six (6) months of the Closing Date,
and shall have given to Seller an opportunity to cure any such breach or default
within a reasonable period of time after Buyer's learning of such breach of
warranty. In no event shall Seller's liability to Buyer by reason of a breach or
default of any or all of the Surviving Warranties exceed $2,000,000.00, and
Seller shall have no liability to Buyer for breach of the Surviving Warranties
except to the extent of the loss incurred by Buyer as a result thereof exceeds
$50,000.00. Any litigation to enforce any Surviving Warranty must be commenced
within three (3) months from the date of the Warranty Notice, and if not
commenced within such time period, Buyer shall be deemed to have waived its
claims for such breach or default.

                  (c) Buyer's obligations under this Agreement as shall possibly
imply performance or observance after the Closing Date shall survive closing,
notwithstanding any presumption to the contrary; without in any manner limiting
the generality of the foregoing provisions of this sentence, the obligations of
Buyer under Paragraphs 7, 16, 18, 19, 20 and 23.

21.      ESCROW PROVISIONS.

                  (a) INVESTMENT OF DEPOSIT. Escrowee shall invest the Deposit
in such accounts, commercial paper, U.S. government securities, repurchase
agreements or other instruments as Buyer shall from time-to-time direct and
Seller may approve. Escrowee shall promptly advise Seller and Buyer of the
investment of the Deposit. All interest earned on the Deposit shall be added to
and deemed part of the Deposit. Interest shall follow the Deposit.

                  (b) PAYMENT AT CLOSING. If the Closing is completed under this
Agreement, Escrowee shall deliver the Deposit to Seller on the Closing Date on
account of the Purchase Price.

                  (c) OTHER PAYMENT. Notwithstanding anything contained in this
Agreement, upon receipt of any written notice from Seller or Buyer claiming the
Deposit pursuant to the provisions of this Agreement, Escrowee shall promptly
forward a copy thereof to the other party and, unless such other party within
ten (10) days thereafter notifies Escrowee of any objection to such request for
the disbursement of the Deposit, Escrowee shall disburse the Deposit to the
party demanding the same and Escrowee shall thereupon be released and discharged
from any further duty or obligation under this Agreement.

                  (d) STAKEHOLDER. Escrowee is acting as a stakeholder only with
respect to the Deposit. If there is any dispute as to whether Escrowee is
obligated to deliver the Deposit, or as to whom the Deposit is to be delivered,
Escrowee may refuse to make any delivery and may continue to hold the Deposit
until receipt by Escrowee of written authorization, signed by both Seller and
Buyer, directing the disposition of the Deposit or, in the absence of such joint
written authorization, until final determination of the rights of the parties in
appropriate judicial proceeding. Escrowee may also bring an appropriate action
or proceeding for leave to deposit the Deposit in a court of competent
jurisdiction and to interplead Seller and Buyer. Upon making delivery of the
Deposit, Escrowee shall have no further liability with respect to the Deposit.
Seller and Buyer agree that the duties of Escrowee in its capacity as escrow
holder under this Agreement are ministerial in nature and that

                                    20 of 25

<PAGE>

Escrowee shall incur no liability except for its willful misconduct or gross
negligence so long as Escrowee acts in good faith.

                  (e)      TAX INFORMATION. The federal tax identification
number of Buyer is 22-3703838.

                  (f)      ESCROW FEES. Seller and Buyer shall each pay
one-half of the fees and expenses, if any, due to Escrowee as compensation for
its escrow services pursuant to this Agreement, and shall each reimburse
Escrowee for one-half of the expenses incurred by Escrowee in discharging its
duties and obligations as escrow holder under this Agreement.

22.      ISRA.

                  (a) EVIDENCE OF ISRA COMPLIANCE. Seller shall use commercially
reasonable efforts to obtain, as appropriate, from the New Jersey Department of
Environmental Protection ("NJDEP"): (i) a Letter of Nonapplicability ("LNA");
(ii) an approval of a Negative Declaration ("Negative Declaration Approval");
(iii) a no further action letter; (iv) an approval of a de minimis quantity
exemption application; (v) an approval of a remediation agreement; or (vi) a
Remediation in Progress Waiver ("Remediation in Progress Waiver," and together
with the items set forth in (i), (ii), (iii), (iv) and (v), "Evidence of ISRA
Compliance"). Seller shall provide Buyer with copies of all filings and
submissions made by Seller pursuant to ISRA concurrently with the delivery of
such filings or submissions to NJDEP and shall also provide Buyer with copies of
all correspondence and responses received from NJDEP promptly after receipt
thereof.

                  (b) ISRA DEFECTS. If Seller shall be unable to obtain Evidence
of ISRA Compliance with respect to any property comprising the Premises (such
failure being referred to herein as an "ISRA Defect"), then the Closing Date
shall be postponed (for a period not to exceed sixty (60) days) until such time
as such ISRA Defect no longer exists. At such time as Seller shall obtain
Evidence of ISRA Compliance with respect to each of the properties comprising
the Premises, such that no ISRA Defect exists prior to the termination of such
sixty (60) day period, the parties shall promptly proceed with the Closing. If
Seller shall be unable to obtain Evidence of ISRA Compliance with respect to
each of the properties comprising the Premises such that an ISRA Defect shall no
longer exist prior to the termination of such sixty (60) day period, each of
Seller and Buyer shall have the right to terminate this Agreement, provided,
however, either party may upon written notice extend such sixty (60) day period
for an additional thirty (30) days.

23.      MISCELLANEOUS.

                  (a) CAPTIONS OR HEADINGS; INTERPRETATION. The captions or
headings of the Paragraphs and subparagraphs of this Agreement are for
convenience only, and shall not control or affect the meaning or construction of
any of the terms or provisions of this Agreement. Wherever in this Agreement the
singular number is used, the same shall include the plural and vice versa and
the masculine gender shall include the feminine gender and vice versa as the
context shall require.


                                    21 of 25

<PAGE>


                  (b) AMENDMENTS AND WAIVERS. No change, alteration, amendment,
modification or waiver of any of the terms or provisions of this Agreement shall
be valid unless the same shall be in writing and signed by Buyer and Seller.

                  (c) NO RULE OF CONSTRUCTION. This Agreement has been
negotiated at arms length by both Seller and Buyer, and no rule of construction
shall be invoked against either party with respect to the authorship thereof or
of any of the documents to be delivered by the respective parties at the
closing.

                  (d) COUNTERPARTS. This Agreement may be executed in
multiple counterparts each of which shall be deemed an original but together
shall constitute one agreement.

                  (e) APPLICABLE LAW. This Agreement shall be governed and
construed according to the laws of the state in which the Premises are located.

                  (f) RIGHT TO WAIVE CONDITIONS OR CONTINGENCY. Either party may
waive any of the terms and conditions of this Agreement made for its benefit
provided such waiver is in writing and signed by the party waiving such term or
condition.

                  (g) PARTIAL INVALIDITY. If any term, covenant, condition or
provision of this Agreement or the application thereof to any person or
circumstance shall be invalid or unenforceable, at any time or to any extent,
the remainder of this Agreement, or the application of such term or provision to
persons or circumstances other than those as to which it is held invalid or
unenforceable, shall not be affected thereby. Each term, covenant, condition and
provision of this Agreement shall be valid and enforced to the fullest extent
permitted by law.

                  (h) CONFIDENTIALITY. Buyer agrees to keep this Agreement
confidential and not make any public announcements or disclosures with respect
to the subject matter of this Agreement without the written consent of Seller.
This provision shall survive Closing.

                  (i) AGREEMENT NOT TO BE RECORDED. This Agreement shall not be
filed of record by or on behalf of Buyer in any office or place of public
record. If Buyer fails to comply with the terms hereof by recording or
attempting to record this Agreement or a notice thereof, such act shall not
operate to bind or cloud the title to the Premises. Seller shall, nevertheless,
have the right forthwith to institute appropriate legal proceedings to have the
same removed from record. If Buyer or any agent, broker or counsel acting for
Buyer shall cause or permit this Agreement or a copy thereof to be filed in an
office or place of public record, Seller, at its option, and in addition to
Seller's other rights and remedies, may treat such act as a default of this
Agreement on the part of Buyer. However, the filing of this Agreement in any
lawsuit or other proceedings in which such document is relevant or material
shall not be deemed to be a violation of this subparagraph 23(i).

                  (j) TIME OF THE ESSENCE. Time, wherever specified herein for
the performance by Seller or Buyer of any of their respective obligations
hereunder, is hereby made and declared to be of the essence of this Agreement.

                                    22 of 25

<PAGE>


                  (k) COMPUTATION OF PERIODS. If the final day of any period of
time in any provision of this Agreement falls upon a Saturday, Sunday or a
holiday observed by federally insured banks in the State in which the Premises
is located or by the United States Postal Service, then, the time of such period
shall be extended to the next day which is not a Saturday, Sunday or holiday.
Unless otherwise specified, in computing any period of time described in this
Agreement, the day of the act or event after which the designated period of time
begins to run is not to be included and the last day of the period is so
computed is to be included, unless such last day is a Saturday, Sunday or
holiday in which event the period shall run until the end of the next day which
is neither a Saturday, Sunday or holiday.

                  (l) EXHIBITS AND SCHEDULES. All exhibits and schedules annexed
to this Agreement, which may be amended from time to time, are incorporated by
reference into and made a part of this Agreement.

                  (m) 1031 EXCHANGE. Seller advises Buyer that Seller may seek
to effectuate a like-kind exchange as permitted under Section 1031 of the
Internal Revenue Code of 1986 ("Code") relating to Seller's sale of the
Premises. If Seller so elects, Buyer agrees to cooperate with Seller in order
that Seller can effectuate a Section 1031 like-kind exchange and agrees to
execute such documents as may be reasonably necessary in order to assist Seller
in consummating such an exchange, including but not limited to, permitting
Seller to assign this Agreement to a qualified intermediary; provided, however,
that:

                           (i)      the total sum to be paid by Buyer for the
Premises shall not exceed or be less than the Purchase Price;

                           (ii)     the Buyer's rights (and the Seller's
obligations to Buyer) respecting all other provisions of this Agreement shall
not be adversely affected by any such exchange, whether or not effected by
Seller;

                           (iii)    Buyer's expenses with respect to the
conveyance of the Premises shall be limited to the expenses it would have to
expend under this Agreement without regard to this subparagraph 23(m) and Seller
shall pay any additional expenses as may be occasioned by such exchange;

                           (iv)     Buyer shall not be required to undertake
contractual or other liabilities or obligations by reason of the exchange other
than the liabilities and obligations undertaken by it under the terms of this
Agreement without regard to this subparagraph 23(m);

                           (v)      Buyer shall not in any way be liable to
Seller or any other party whatsoever for any failure of the transaction to
qualify as a tax free exchange under the Code; and

                           (vi)     Seller retains the right, but not the
obligation, to prepare and provide to the qualified intermediary an allocation
of the Purchase Price with respect to the Premises in order to facilitate the
1031 exchange; and

                                    23 of 25

<PAGE>


                           (vii)    Buyer shall not be obligated to take title
to the exchange properties (i.e., the property which Seller seeks to acquire).


                                    24 of 25

<PAGE>


         IN WITNESS WHEREOF, the parties, intending legally to be bound, have
executed this Agreement as of the date first above written.


                                     SELLER:


                                     NEW JERSEY ASSOCIATES, a New Jersey
                                     general partnership


                                     By:     KEYSTONE PROPERTY TRUST, a
                                             Maryland real estate investment
                                             trust, its managing general partner


                                     By:     /s/ STEPHEN J. BUTTE
                                             ----------------------------------
                                             Name:  Stephen J. Butte
                                             Title: Senior Vice President


                                     BUYER:


                                     FAWN REALTY L.L.C., a New Jersey limited
                                     liability company


                                     By:  Fawn Realty Corp., a New Jersey
                                          corporation


                                     BY:  /s/ RICHARD STADTMAUER
                                          -------------------------------------
                                          Name:  Richard Stadtmauer
                                          Title: Vice President


                                     Agreed to and Acknowledged with respect to
                                     the obligations set forth in Paragraphs 2,
                                     3, 4, 12, 14 and 21 of this Agreement


                                    ESCROWEE:

                                    CHICAGO TITLE INSURANCE COMPANY,
                                    c/o PROFESSIONAL ABSTRACT & TITLE
                                    AGENCY, INC.

                                    By:  /s/ ANDREW C. SWIDER
                                         --------------------------------------
                                         Name:  Andrew C. Swider
                                         Title: Officer


                                    25 of 25