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                                  EXHIBIT 10.69


               PURCHASE AND SALE AGREEMENT AND ESCROW INSTRUCTIONS
                         FOR THE AGILENT BOSTON BUILDING

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                           PURCHASE AND SALE AGREEMENT
                             AND ESCROW INSTRUCTIONS


                                 BY AND BETWEEN

           BPF TECH CENTRAL, LLC, a Delaware limited liability company

                                   ("Seller")


                                       AND


        WELLS OPERATING PARTNERSHIP, L.P., a Delaware limited partnership


                                    ("Buyer")

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                                Table of Contents
                                -----------------

<TABLE>
<CAPTION>
                                                                                           Page
                                                                                           ----
<S>                                                                                        <C>
1.   BASIC TERMS AND DEFINITIONS; REFERENCES ...............................................  1
  1.1     Basic Terms and Definitions ......................................................  1
  1.2     References .......................................................................  1
2.   PURCHASE AND SALE .....................................................................  2
3.   PURCHASE PRICE; DEPOSIT AND INDEPENDENT CONSIDERATION .................................  2
  3.1     Purchase Price ...................................................................  2
  3.2     Payment of Purchase Price ........................................................  3
  3.3     Disposition of Deposit Upon Failure to Close .....................................  3
  3.4     Independent Contract Consideration ...............................................  3
4.   PROPERTY INFORMATION; TITLE REVIEW; INSPECTIONS AND DUE DILIGENCE; TENANT
ESTOPPEL CERTIFICATES; CONFIDENTIALITY .....................................................  3
  4.1     Property Information .............................................................  3
  4.2     Title and Survey Review; Title Policy ............................................  4
    4.2.1   Delivery of Title Report .......................................................  4
    4.2.2   Title Review and Cure ..........................................................  4
    4.2.3   Delivery of Title Policies at Closing ..........................................  5
  4.3     Inspections; Due Diligence Period ................................................  5
    4.3.1   Inspections in General .........................................................  5
    4.3.2   Environmental Inspections ......................................................  5
    4.3.3   Termination During Due Diligence Period ........................................  6
  4.4     Tenant Estoppel Certificates .....................................................  6
  4.5     Service Contracts ................................................................  6
  4.6     Confidentiality ..................................................................  6
5.   OPERATIONS AND RISK OF LOSS ...........................................................  6
  5.1     Ongoing Operations ...............................................................  6
  5.2     New Contracts ....................................................................  6
  5.3     Leasing Arrangements .............................................................  7
  5.4     Damage or Condemnation ...........................................................  7
  5.5     Warranty Work Contract ...........................................................  7
6.   SELLER'S AND BUYER'S DELIVERIES .......................................................  8
  6.1     Seller's Deliveries into Escrow ..................................................  8
  6.2     Buyer's Deliveries into Escrow ...................................................  9
  6.3     Closing Statements/Escrow Fees; Tenant Notices ...................................  9
  6.4     Post-Closing Deliveries ..........................................................  9
7.   CONDITIONS TO BUYER'S AND SELLER'S OBLIGATIONS ........................................  9
  7.1     Conditions to Buyer's Obligations ................................................  9
  7.2     Conditions to Seller's Obligations ............................................... 11
8.   CLOSE OF ESCROW; POSSESSION ........................................................... 11
  8.1     Close of Escrow .................................................................. 11
9.   ESCROW ................................................................................ 12
  9.1     Closing .......................................................................... 12
  9.2     Escrow and Title Charges ......................................................... 12
  9.3     Procedures Upon Failure of Condition ............................................. 13
10.  PRORATIONS ............................................................................ 13
  10.1    Collected Rent ................................................................... 13
  10.2    Operating Costs and Additional Rent Reconciliation ............................... 14
  10.3    Taxes and Assessments ............................................................ 14
  10.4    Leasing Commissions, Tenant Improvements and Service Contracts ................... 15
  10.5    Intentionally Omitted ............................................................ 15
  10.6    Utilities and Utility Deposits ................................................... 15
  10.7    Owner Deposits ................................................................... 15
</TABLE>

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<TABLE>
<S>                                                                           <C>
  10.8    Final Adjustment After Closing .....................................  15
  10.9    No Marketing of Property ...........................................  16
11.     SELLER'S REPRESENTATIONS AND WARRANTIES; AS-IS .......................  16
  11.1    Seller's Representations and Warranties ............................  16
  11.2    As-Is ..............................................................  17
12.     BUYER'S COVENANTS, REPRESENTATIONS AND WARRANTIES; RELEASE; ERISA ....  18
  12.1    Authority ..........................................................  18
  12.2    Release ............................................................  19
  12.3    ERISA ..............................................................  20
  12.4    Warranty Work ......................................................  20
13.     DEFAULT AND DAMAGES ..................................................  20
  13.1    DEFAULT BY BUYER ...................................................  20
  13.2    Default by Seller ..................................................  21
14.     BROKER'S COMMISSIONS .................................................  21
15.     MISCELLANEOUS PROVISIONS .............................................  21
  15.1    Notices ............................................................  21
  15.2    Assignment; Binding on Successors and Assigns ......................  22
  15.3    Work Product .......................................................  23
  15.4    Further Assurances; Completion of Warranty Work ....................  23
  15.5    Attorneys' Fees ....................................................  23
  15.6    Survival of Representations, Warranties and Agreements .............  23
  15.7    Entire Agreement ...................................................  23
  15.8    Governing Law ......................................................  24
  15.9    Counterparts .......................................................  24
  15.10   Headings; Construction .............................................  24
  15.11   Time of Essence ....................................................  24
  15.12   Partial Validity; Severability .....................................  24
  15.13   No Third Party Beneficiaries .......................................  24
  15.14   Recordation of Agreement ...........................................  24
  15.15   Joint Product of Parties ...........................................  24
  15.16   Calculation of Time Periods ........................................  24
  15.17   Procedure for Indemnity ............................................  25
  15.18   Section 1031 Exchange ..............................................  25
  15.19   Waiver of Jury Trial ...............................................  25
  15.20   No Personal Liability ..............................................  25
  15.21   Joint and Several Liability ........................................  25
  15.22   No Waiver ..........................................................  25
  15.23   Latent Defects .....................................................  25
</TABLE>

                                      -ii-

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                           PURCHASE AND SALE AGREEMENT
                             AND ESCROW INSTRUCTIONS

     THIS PURCHASE AND SALE AGREEMENT AND ESCROW INSTRUCTIONS (this "Agreement")
is made and entered into as of April 5, 2002, between BPF Tech Central, LLC, a
Delaware limited liability company ("Seller"), and WELLS Operating Partnership,
L.P., a Delaware limited partnership ("Buyer"), with reference to the following:

     A.   Seller is the owner of the improved real property (the "Real
Property") described on Exhibit A attached hereto together with certain personal
property located upon or used in connection with such improved real property and
certain other assets relating thereto, all as more particularly described in
Section 2 hereof.

     B.   Seller desires to sell to Buyer, and Buyer desires to purchase from
Seller, the Real Property, together with certain personal property and related
assets on the terms and subject to the conditions contained in this Agreement.

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

1.   BASIC TERMS AND DEFINITIONS; REFERENCES

     1.1  Basic Terms and Definitions.

          (a)  Effective Date. The effective date of this Agreement is the date
set forth above ("Effective Date").

          (b)  Closing Date. The day that Close of Escrow shall occur is April
18, 2002 (the "Closing Date").

          (c)  Title Review Period. The "Title Review Period" shall end on April
12, 2002 at 5:00 p.m. (Massachusetts time).

          (d)  Due Diligence Period. The "Due Diligence Period" shall end on
April 12, 2002 at 5:00 p.m. (Massachusetts time).

          (e)  Escrow Holder. The escrow holder shall be Chicago Title Company
("Escrow Holder"), whose address is National Business Unit, 16969 Von Karman,
Irvine, California 92606, Escrow Officer: Joy Eaton; Telephone: (949) 263-0123;
Telecopier: (949) 263-0356.

          (f)  Title Company. The title company shall be Chicago Title Insurance
Company ("Title Company") whose address is National Business Unit, 16969 Von
Karman, Irvine, California 92606, Title Coordinator: John Premac; Telephone:
(949) 263-0123; Telecopier: (949) 263-0356.

          (g)  Agilent Lease. The "Agilent Lease" is that certain lease dated
December 7, 2002 between Seller and Agilent Technologies, Inc.

     1.2  References. All references to Exhibits refer to Exhibits attached to
this Agreement and all such Exhibits are incorporated herein by reference. The
words "herein," "hereof," "hereinafter" and words of similar import refer to
this Agreement as a whole and not to any particular Section hereof.

                                      -1-

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2.   PURCHASE AND SALE.

     Subject to the terms and conditions of this Agreement, Seller agrees to
sell, assign and transfer to Buyer and Buyer agrees to purchase from Seller, for
the purchase price set forth in Section 3 hereof, all of Seller's right, title
and interest in and to the following (collectively, the "Property"):

     2.1  The Real Property, together with the buildings located thereon, and
all associated parking areas, landscaping and fixtures and all other
improvements located thereon (the buildings and such other improvements are
referred to herein collectively as the "Improvements"); all references
hereinafter made to the Real Property shall be deemed to include all rights,
privileges, licenses, easements, tenements and appurtenances benefiting the Real
Property and/or the Improvements situated thereon, including, without
limitation, all mineral and water rights and all easements, rights-of-way and
other appurtenances used or connected with the beneficial use or enjoyment of
the Real Property;

     2.2  All personal property, equipment, machinery, supplies and fixtures
(collectively, the "Personal Property") listed on Exhibit B attached hereto or
otherwise left on the Real Property at the Close of Escrow (as defined in
Section 8.1 hereof) to the extent owned by Seller (exclusive of the chiller
units serving the property commonly know as 80 Central Street, Boxborough,
Massachusetts);

     2.3  All of Seller's interest in any intangible property (expressly
excluding the names "Koll," "Bren", "K/B", "KBS" or any derivative thereof, or
any name that includes the word "Koll", the word "Bren", the word "Schreiber",
the word "K/B" or the word "KBS", or any derivative thereof) used or useful in
connection with the foregoing, including, without limitation, any right Seller
has in the name(s) of the building situated on the Real Property, including, but
not limited to, the name "Tech Central @ Boxborough" or any derivation thereof,
all contract rights, warranties related to the construction of the Improvements
(including without limitation the warranties listed on Schedule 3 attached
hereto and made a part hereof), guaranties, licenses, permits, entitlements,
governmental approvals and certificates of occupancy which benefit the Real
Property and/or the Personal Property. (Notwithstanding the foregoing, Seller
and Buyer agree and acknowledge that any assignable guaranties and warranties ,
as they relate to the wastewater treatment facility servicing the Property,
shall be assigned by Seller to Buyer and to the owner of the property commonly
known as 80 Central Street, Boxborough, Massachusetts);

     2.4  All of Seller's interest in the leases (and all amendments thereto)
listed in Schedule 5 attached hereto and made a part hereof and all other leases
hereinafter entered into by Seller affecting the Real Property as of the Close
of Escrow to the extent permitted by the terms of this Agreement (collectively,
the "Leases"); and

     2.5  All of Seller's interests in the service contracts listed on Exhibit C
attached hereto and all service contracts hereafter entered into by Seller to
the extent permitted by the provisions of this Agreement (the "Service
Contracts").

Notwithstanding anything to the contrary contained herein, the term "Property"
shall expressly exclude any Rents (as such term is defined in Section 10.1
hereof) or any other amounts payable by tenants under the Leases for periods
prior to the Close of Escrow, any Rent or other amounts payable by any former
tenants of the Property, and any judgments, stipulations, orders, or settlements
with any tenants under the Leases or former tenants of the Property relating to
the period ending at the Close of Escrow (hereinafter collectively referred to
as the "Excluded Property").

3.   PURCHASE PRICE; DEPOSIT AND INDEPENDENT CONSIDERATION.

     3.1  Purchase Price. The purchase price for the Property shall be Thirty
Five Million One Hundred Fifty Thousand and 00/100 Dollars ($35,150,000) less
amounts credited to Buyer pursuant to Section 10.4.

                                      -2-

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     3.2    Payment of Purchase Price. The Purchase Price shall be payable as
follows:

            3.2.1  Within two (2) business days following the Effective Date,
and as a condition precedent to the effectiveness hereof, Buyer shall deposit in
escrow with Escrow Holder (as defined in Section 9.1 hereof), in cash or current
funds, the sum of Five Hundred Thousand and 00/100 Dollars ($500,000) (the
"Deposit"). Immediately upon Escrow Holder's receipt of the Deposit (the
"Opening of Escrow"), Escrow Holder shall invest the same in a federally insured
interest-bearing account acceptable to Seller and Buyer, with all interest
accruing thereon credited to the Purchase Price. For purposes of this Agreement,
any interest accruing on the Deposit from time to time shall be deemed part of
the Deposit. Upon expiration of the Due Diligence Period, if Buyer has not
previously terminated this Agreement by its terms the Deposit shall become
nonrefundable except as otherwise provided herein .

            3.2.2  Provided all the conditions in Section 7.1 hereof have been
satisfied or waived by Buyer, Buyer shall deposit in cash or current funds with
Escrow Holder no later than 2:00 p.m. (California time) one (1) business day
prior to the Closing Date (as defined in Section 1.1(b) hereof) an amount equal
to the Purchase Price less the Deposit and all interest accrued thereon plus or
minus applicable prorations pursuant to Section 10 hereof.

     3.3    Disposition of Deposit Upon Failure to Close. If the Close of Escrow
fails to occur due to Buyer's default under this Agreement (all of the
conditions to Buyer's obligation to close having been satisfied or waived), then
the disposition of the Deposit and all interest accrued thereon shall be
governed by Section 13.1 hereof; if the Close of Escrow fails to occur due to
Seller's default under this Agreement (all of the conditions to Seller's
obligation to close having been satisfied or waived), then the Deposit and all
interest accrued thereon shall promptly be refunded to Buyer; and if the Close
of Escrow fails to occur due to the failure of any of the conditions set forth
in Sections 7.1 or 7.2 hereof other than as a result of Buyer's or Seller's
default under this Agreement, then the disposition of the Deposit and all
interest accrued thereon shall be governed by Section 9.3 hereof.

     3.4    Independent Contract Consideration. In addition to the Earnest
Money, Buyer has as of the date hereof delivered to Seller the amount of ONE
HUNDRED AND NO/100 DOLLARS ($100.00), the receipt and sufficiency of which is
hereby acknowledged by Seller (the "Independent Contract Consideration"), which
amount Seller and Buyer agree has been bargained for as consideration for
Seller's execution and delivery of this Agreement and Buyer's right to inspect
the Property pursuant to Section 4.3 of the Agreement. The Independent Contract
Consideration is in addition to and independent of any other consideration or
payment provided for in this Agreement and is non-refundable in all events.

4.   PROPERTY INFORMATION; TITLE REVIEW; INSPECTIONS AND DUE DILIGENCE; TENANT
     ESTOPPEL CERTIFICATES; CONFIDENTIALITY.

     4.1    Property Information. Seller shall make available to Buyer within
five (5) business days after the date of this Agreement, to the extent in
Seller's possession, the following, all of which shall be made available for
review and copying (at Buyer's cost and expense) at the offices of Insignia/EGS,
Inc., 111 Huntington Avenue, Boston, Massachusetts (collectively, the "Property
Information"):

            (a)  the Leases;

            (b)  a current rent roll for the Real Property, indicating rents
collected, scheduled rents and concessions, delinquencies, and security deposits
held (collectively, the "Rent Rolls");

            (c)  the most current operating statements for the Real Property, if
available (collectively, the "Operating Statements");

            (d)  the projected operating expenses for the Property for 2002;

            (e)  copies of the Service Contracts;

                                      -3-

<PAGE>

            (f)  existing land title surveys, if any, for the Real Property
(collectively, the "Existing Surveys");

            (g)  Commission Agreements (as hereinafter defined);

            (h)  copies of any existing title insurance policies for the Real
Property in Seller's possession;

            (i)  any environmental, soils and/or engineering reports prepared
for Seller or Seller's predecessors (including any relating to the wastewater
treatment facility servicing the Property);

            (j)  any plans and specifications, permits, licenses, zoning
approvals, certificates of occupancy, warranties, lien waivers, utility
arrangements and all other materials directly related to the existing
development and construction of the Property (including any relating to the
wastewater treatment facility servicing the Property); and

            (k)  copies of any written notices from tenants or governmental
authorities received during Seller's ownership of the Property.

Under no circumstances shall Buyer be entitled to review any appraisals relating
to the Property or any internal financial audits relating to the Property.

     4.2    Title and Survey Review; Title Policy.

            4.2.1  Delivery of Title Report. Seller shall request, at Buyer's
expense, the Title Company to promptly deliver to Seller and Buyer a preliminary
report or title commitment covering the Real Property (the "Title Report")
issued by the Title Company, together with copies of all documents
(collectively, the "Title Documents") referenced in the Title Report (including,
without limitation, copies of the deed pursuant to which Seller obtained title
to the Real Property). Seller shall assist Buyer, at Buyer's expense, to obtain
a new survey for the Real Property (such survey being referred to herein as the
"New Survey"). Buyer understands and acknowledges that if Buyer elects to obtain
a New Survey or an updated or recertified survey for the Real Property the
completion and/or delivery of the surveys or updated or recertified surveys
shall not be a condition precedent to the Close of Escrow. Notwithstanding the
foregoing, Buyer further acknowledges that Seller makes no representations or
warranties, and Seller shall have no responsibility, with respect to the
completeness of the Title Documents made available to Buyer.

            4.2.2  Title Review and Cure. Commencing from the date of this
Agreement and continuing through and including the Title Review Period, Buyer
shall have the right to approve or disapprove the condition of title to the Real
Property. On or before the expiration of the Title Review Period, Buyer shall
deliver to Seller and Escrow Holder written notice ("Buyer's Title Notice") of
Buyer's approval or disapproval of the matters reflected in the Title Report and
the New Survey, if any (or any Existing Survey if Buyer elects not to obtain a
New Survey); Buyer's Title Notice delivered by Buyer to Seller must state that
it is a "Buyer's Title Notice being delivered in accordance with the provisions
of Section 4.2.2 of the Purchase Agreement." The failure of Buyer to deliver to
Seller Buyer's Title Notice on or before the expiration of the Title Review
Period shall be deemed to constitute Buyer's approval of the condition of title
to the Real Property, other than the monetary encumbrances described below. If
Buyer disapproves any matter of title shown in the Title Report, the New Survey,
if any (or any Existing Survey if Buyer elects not to obtain a New Survey) other
than matters of record evidencing financial obligations of Seller to Guaranty
Federal Bank F.S.B., or any other monetary encumbrances voluntarily granted by
Seller, then this Agreement shall automatically terminate, the parties shall be
released from all further obligations under this Agreement (except pursuant to
any provisions which by their terms survive a termination of this Agreement),
the Deposit shall be immediately returned to Buyer and Buyer shall immediately
return all Property Information to Seller. Whether or not Buyer delivers a
Buyer's Title Notice, Seller shall cause the Title Company to remove from the
Title Policy (as hereinafter defined in Section 4.2.3) in accordance with
customary conveyancing practices, all matters of record evidencing financial
obligations of Seller to Guaranty Federal Bank F.S.B. or any other monetary
encumbrances voluntarily granted by Seller. Buyer shall have been deemed to have
approved any title exception

                                      -4-

<PAGE>

that Seller is not obligated to remove and to which either Buyer did not object
as provided above, or to which Buyer did object, but with respect to which Buyer
did not terminate this Agreement.

            4.2.3  Delivery of Title Policies at Closing. As a condition
precedent to the Close of Escrow, the Title Company shall have issued and
delivered to Buyer, or shall have committed to issue and deliver to Buyer, with
respect to the Real Property, an ALTA Owner's Policy of Title Insurance (1992
Form) (the "Title Policy") issued by the Title Company as of the date and time
of the recording of the Deed (as such term is defined in Section 6.1 hereof) for
the Real Property , in the amount of the Purchase Price insuring Buyer as owner
of good, marketable and indefeasible fee simple title to the Real Property,
subject to the Permitted Exceptions as hereinafter defined. For purposes of this
Agreement, "Permitted Exceptions" shall mean and include (a) matters affecting
the Real Property which are created by or with the written consent of Buyer, (b)
the rights of the tenants under the Leases affecting the Real Property, (c) all
exceptions disclosed by the Title Report relating to the Real Property and which
are approved or deemed approved by Buyer in accordance with Section 4.2.2
hereof, (d) all applicable laws, ordinances, rules and governmental regulations
(including, without limitation, those relating to building, zoning and land use)
affecting the development, use, occupancy or enjoyment of the Real Property and
(e) all matters shown on the Existing Survey or the New Survey.

     4.3    Inspections; Due Diligence Period.

            4.3.1  Inspections in General. Commencing from the Effective Date
and continuing through and including the expiration of the Due Diligence Period,
Buyer, its agents, and employees shall have a limited license (the "License") to
enter upon the Real Property for the purpose of making non-invasive inspections
at Buyer's sole risk, cost and expense. Before any such entry, Buyer shall
provide Seller with evidence that it maintains insurance with an insurer and
with insurance limits and coverage reasonably satisfactory to Seller. All of
such entries upon the Real Property shall be at reasonable times during normal
business hours and after at least 48 hours prior notice to Seller or Seller's
agent, and Seller or Seller's agent shall have the right to accompany Buyer
during any activities performed by Buyer on the Real Property. Notwithstanding
anything stated to the contrary herein, Buyer shall have no right to inspect any
of the occupied space in the Real Property, Buyer shall not contact or speak to
any of the tenants under the Leases, and such inspections shall not unreasonably
interfere with the rights of tenants; provided, however, notwithstanding the
foregoing, Buyer shall have the right to inspect occupied space in the Real
Property and to contact or speak to tenants provided that (a) Buyer provides
Seller with no less than 24 hours prior written notice of such intention, (b)
Seller or Seller's representative is present (unless Seller waives such
requirement)during such inspections and/or discussions with tenants, and (c) any
discussions with tenants is limited to their existing tenancy and premises and
does not involve any lease renegotiations. At Seller's request, Buyer shall
provide Seller (at no cost to Seller and without any representation or warranty
by Buyer) with a copy of the results of any tests and inspections made by Buyer,
excluding only market and economic feasibility studies, any appraisals and any
internal financial audits or reports relating to the Property. If any inspection
or test disturbs the Real Property, Buyer will restore the Real Property to the
same condition as existed before the inspection or test. Buyer shall defend,
indemnify Seller and hold Seller, Seller's trustees, beneficiaries, officers,
directors, members, representatives, principals, partners, shareholders,
employees, agents, contractors and tenants and the Real Property harmless from
and against any and all losses, costs, damages, claims, or liabilities,
including but not limited to, mechanic's and materialmen's liens and Seller's
attorneys' fees, arising out of or in connection with Buyer's inspection of the
Real Property; provided that Buyer shall not be responsible for indemnifying or
holding any such parties harmless for the mere discovery of any existing
condition at the Property. The License shall be deemed revoked upon termination
of this Agreement. The provisions of this paragraph shall survive the Close of
Escrow or the earlier termination of this Agreement.

            4.3.2  Environmental Inspections. The inspections under Section
4.3.1 may include non-invasive Phase I environmental inspections of the Real
Property, but no Phase II environmental inspections or other invasive
inspections or sampling of soil or materials, including without limitation
construction materials, either as part of the Phase I inspections or any other
inspections, shall be performed without the prior written consent of Seller,
which may be withheld in its sole and absolute discretion, and if consented to
by Seller, the proposed scope of work and the party who will perform the work
shall be subject to Seller's review and approval. At Seller's request, Buyer
shall deliver to Seller (at no cost to Seller and without any representation or
warranty by Buyer) copies of any Phase II or other environmental reports to
which Seller consents as provided above.

                                      -5-

<PAGE>

            4.3.3  Termination During Due Diligence Period. If Buyer determines,
in its sole discretion, before the expiration of the Due Diligence Period, that
the Real Property is unacceptable for Buyer's purposes, Buyer shall have the
right to terminate this Agreement by giving to Seller notice of termination
("Termination Notice") before the expiration of the Due Diligence Period, in
which event the Deposit shall be immediately refunded to Buyer, Buyer shall
immediately return all Property Information to Seller and, except for those
provisions of this Agreement which expressly survive the termination of this
Agreement, the parties hereto shall have no further obligations hereunder. If
Buyer fails to deliver a Termination Notice to Seller and Escrow Holder on or
before the expiration of the Due Diligence Period, then Buyer shall be deemed to
be satisfied with all aspects of all the Real Property, including, without
limitation, the condition and suitability of all the Real Property for Buyer's
intended use, and Buyer shall be obligated to acquire the Real Property in
accordance with the provisions of this Agreement (but subject to the provisions
of Section 7 hereof). Buyer's delivery of a Termination Notice to Seller with
respect to the Real Property shall constitute Buyer's election to terminate this
Agreement with respect to the Real Property as provided above in this Section
4.3.3.

     4.4    Tenant Estoppel Certificates. Seller shall endeavor to secure and
deliver to Buyer no later than five (5) days prior to the expiration of the Due
Diligence Period estoppel certificates for all Leases consistent with the
information in the Rent Rolls and in the Leases and substantially in the form
attached hereto as Exhibit D or such form as may be required under the
applicable Leases.

     4.5    Service Contracts. Buyer shall assume the obligations arising from
and after the Closing Date under the Service Contracts.

     4.6    Confidentiality. Prior to the Close of Escrow or in the event the
Close of Escrow never occurs, the Property Information and all other
information, other than matters of public record or matters generally known to
the public, furnished to, or obtained through inspection of the Real Property
by, Buyer, its affiliates, lenders, employees, attorneys, accountants and other
professionals or agents relating to the Real Property, will be treated by Buyer,
its affiliates, lenders, employees and agents as confidential, and will not be
disclosed to anyone (except as reasonably required in connection with Buyer's
evaluation of the Real Property (including appropriate members of the
broker-dealer community selling the products of Buyer or its affiliates) and in
connection with Buyer's activities in closing the transaction contemplated by
this Agreement) except to Buyer's consultants who agree to maintain the
confidentiality of such information, and will be returned to Seller by Buyer if
the Close of Escrow does not occur. The terms of this Agreement will not be
disclosed to anyone prior to the Close of Escrow except to Buyer's and Seller's
consultants (including appropriate members of the broker-dealer community
selling the products of Buyer or its affiliates) who agree to maintain the
confidentiality of such information. After the Close of Escrow, Buyer may
disclose the terms of this Agreement so long as Buyer does not make any material
disclosures of matters Buyer typically would not disclose in similar
transactions. Prior to the Close of Escrow, Seller and Buyer agree not to make
any public announcements or public disclosures or communicate with any media
with respect to the subject matter hereof without the prior written consent of
the other party (in their sole and absolute discretion). The confidentiality
provisions of this Section 4.6 shall not apply to any disclosures made by Buyer
or Seller as required by law, by court order, or in connection with any subpoena
served upon Buyer or Seller; provided Buyer and Seller shall provide each other
with written notice before making any such disclosure.

5.   OPERATIONS AND RISK OF LOSS

     5.1    Ongoing Operations. During the pendency of this Agreement, but
subject to the limitations set forth below, Seller shall carry on its businesses
and activities relating to the Real Property substantially in the same manner as
it did before the date of this Agreement. The new and pending lease transactions
(the "New and Pending Lease Transactions") reflected on Schedule "1" attached
hereto shall be deemed approved by Buyer for purposes of this Agreement.

     5.2    New Contracts. Prior to the expiration of the Due Diligence Period,
Seller may without Buyer's consent enter into contracts (other than new leases
or documents amending the Lease) relating to the Real Property, provided that
Seller provides Buyer with written notice of the same on or before the
expiration of the Due Diligence Period and provided the same can be terminated
without cause on thirty (30) days' notice without the payment of a termination
fee. Following the expiration of the Due Diligence Period, Seller will not enter
into any contract that

                                      -6-

<PAGE>

will be an obligation affecting the Real Property subsequent to the Close of
Escrow (except contracts entered into in the ordinary course of business that
are terminable without cause on 30-days' notice and without the payment of a
termination fee), without the prior consent of the Buyer, which shall not be
unreasonably withheld or delayed. Concurrently with the Close of Escrow, Seller
shall cause any management agreement to which it is a party and which relates to
the Property (exclusive of any contract to operate the wastewater treatment
facility) to be terminated. The provisions of this Section 5.2 shall not apply
to any amendments to the construction contract and the architectural contract
listed on Exhibit I attached hereto, which shall remain Seller's obligations
following the Closing.

     5.3    Leasing Arrangements. Seller may, upon notice to Buyer, but without
Buyer's consent, enter into subleases to the extent required by existing leases
(i.e. Seller's consent is not required or must be granted). Prior to the
expiration of the Due Diligence Period, Seller may enter into new leases of
space in the Real Property and amendments, expansions and renewals of the
Leases, provided that Seller provides Buyer with prior written notice of the
same on or before the expiration of the Due Diligence Period and provided that
Buyer approves the same in writing, which approval shall not be unreasonably
withheld or delayed. Following the expiration of the Due Diligence Period,
Seller shall obtain Buyer's consent, which Buyer may withhold or delay in its
sole discretion, before entering into any new lease of space in the Real
Property and before entering into a Lease amendment, expansion, or renewal.
Buyer shall be deemed to have consented to any new lease or any Lease amendment,
expansion, or renewal if it has not notified Seller specifying with
particularity the matters to which Buyer reasonably objects, within 7 days after
its receipt of Seller's written request for consent, together with a copy of the
Lease amendment, expansion, or renewal or the new lease. At the Close of Escrow,
Buyer shall reimburse Seller for the following in connection with the new Leases
hereafter entered into as permitted by the terms of this Agreement: commissions,
and the cost of tenant improvements, paid by Seller with respect thereto and
with respect to all other Lease amendments, expansions or renewals or new leases
that were entered into pursuant to this Section 5.3 and, at Close of Escrow,
shall assume in writing (pursuant to the Assignment of Leases and Contracts and
Bill of Sale) Seller's obligations under such commission agreements and
contracts for tenant improvements.

     5.4    Damage or Condemnation. Risk of loss resulting from any condemnation
or eminent domain proceeding which is commenced or has been threatened against
the Real Property before the Close of Escrow, and risk of loss to the Real
Property due to fire, flood or any other cause before the Close of Escrow, shall
remain with Seller. If before the Close of Escrow the Real Property or any
portion thereof shall be materially damaged, or if the Real Property or any
material portion thereof shall be subjected to a bona fide threat of
condemnation or shall become the subject of any proceedings, judicial,
administrative or otherwise, with respect to the taking by eminent domain or
condemnation, then Buyer may elect not to acquire the Real Property by
delivering written notice of such election to Seller within five (5) days after
Buyer learns of the damage or taking, in which event Buyer shall no longer be
obligated to purchase, and Seller shall no longer be obligated to sell, the Real
Property. If the Closing Date is within the aforesaid 5-day period, then the
Close of Escrow shall be extended to the next business day following the end of
said 5-day period. If no such election is made, and in any event if the damage
is not material, this Agreement shall remain in full force and effect, the
purchase contemplated herein, less any interest taken by eminent domain or
condemnation, shall be effected with no further adjustment, and upon the Close
of Escrow, Seller shall assign, transfer and set over to Buyer all of the right,
title and interest of Seller in and to any awards that have been or that may
thereafter be made for such taking, and Seller shall assign, transfer and set
over to Buyer any insurance proceeds that may thereafter be made for such damage
or destruction giving Buyer a credit at the Close of Escrow for any deductible
under such policies. For purposes of this Section 5.4, the phrase(s) (i)
"Material damage" or "Materially damaged" means damage reasonably exceeding five
percent of the Purchase Price of the Real Property or damage which entitles any
tenant to terminate its Lease (unless such right is waived), and (ii) "material
portion" means any portion of the Real Property that has a "fair market value"
exceeding 5% of the Purchase Price of the Real Property.

     5.5    Warranty Work Contract. Seller intends to enter into the Warranty
Work Contract. It is anticipated that the work to be performed under the
Warranty Work Contract will not be completed prior to the Closing. Seller agrees
to use commercially reasonable efforts to cause such work as is completed prior
to the Closing to be completed in a good and workmanlike manner, without any
liens being imposed, and on a timely basis. Buyer shall receive a credit at the
Closing in connection with the Warranty Work Contract as set forth in Section
10.4.

                                      -7-

<PAGE>

6.   SELLER'S AND BUYER'S DELIVERIES

     6.1    Seller's Deliveries into Escrow. No later than 2:00 p.m. (California
time) one (1) business day prior to the Closing Date, Seller shall deliver into
Escrow (as such term is defined in Section 9 hereof) to the Escrow Holder the
following:

            (a)  Deed. A deed (the "Deed") in the form attached hereto as
Exhibit E, executed and acknowledged by Seller, conveying to Buyer Seller's
title to the Real Property.

            (b)  Assignment of Leases and Contracts and Bill of Sale. An
Assignment of Leases and Service Contracts and Bill of Sale ("Assignment of
Leases and Contracts and Bill of Sale") in the form of Exhibit F attached
hereto, executed by Seller.

            (c)  State Law Disclosures. Such disclosures and reports as are
required by applicable state and local law in connection with the conveyance of
the Real Property.

            (d)  FIRPTA. A Foreign Investment in Real Property Tax Act affidavit
executed by Seller substantially in the form of Exhibit G attached hereto.

            (e)  Owner's Affidavit. An owner's affidavit in the form of Exhibit
J attached hereto, executed by Seller, and which is sufficient to allow the
Title Company to delete the so-called "standard exceptions" for parties in
possession and mechanics' lines.

            (f)  Broker's Release. A release from Seller's broker, confirming
Seller's broker has received payment of all brokerage commissions payable in
connection with the purchase and sale of the Property.

            (g)  Additional Documents. Any additional documents that Escrow
Holder or the Title Company may reasonably require for the proper consummation
of the transaction contemplated by this Agreement, including without limitation,
documents evidencing Seller's legal existence, good standing and evidence of
authority.

            (h)  Letters to Certain Parties. Letters from Seller to each party
to the Service Contracts and the construction contract and the architectural
contract listed on Exhibit I attached hereto, and to each party warranting the
wastewater treatment facility servicing the Property informing such parties of
the change in the ownership of the Property and the assignment of warranties
thereunder to Buyer (or, in the case of the warranties under the wastewater
treatment facility, to Buyer and the owner of the property commonly known as 80
Central Street, Boxborough, Massachusetts) and, if required under any such
contract or warranty, the written consent of the party thereto.

            (i)  Lien Waiver. A copy of the final lien waiver from Aberthaw
Construction Company, Inc. with respect to all work performed under the
construction contract listed on Exhibit I attached hereto, other than the
Warranty Work (hereinafter defined in Section 6.1(j).

            (j)  Warranty Work Escrow Agreement. An original escrow agreement
between Seller and Buyer and Brown Rudnick Berlack Israels LLP in the form
attached hereto as Exhibit K, ("Escrow Agreement") with respect to Seller's
causing Aberthaw Construction Company, Inc. to perform certain landscaping, the
replacement of panels on the facade of the building at 90 Central Street, and
the replacement of bathroom tiles at 90 Central Street ("Warranty Work").

            (k)  Update Certificate. An update of Seller's representations and
warranties under Section 11.1.

                                       -8-

<PAGE>

            (l)  Notice to Permitting Authorities. Evidence that Seller has
notified the Massachusetts Department of Environmental Protection and the Town
of Boxborough Planning Board of the sale of the Real Property no later than
thirty (30) days prior to the Closing Date.

            (m)  Groundwater Discharge Permit Transfer Agreement. An original
agreement, executed by Seller, in form and substance reasonably acceptable to
Seller, transferring the Groundwater Discharge Permit for the wastewater
treatment facility servicing the Property to Buyer and/or the owner of the
property commonly known as 80 Central Street, Boxborough, Massachusetts
("Transfer Agreement").

     6.2    Buyer's Deliveries into Escrow. No later than 2:00 p.m. (California
time) one (1) business day prior to the Closing Date, Buyer shall deliver into
Escrow to the Escrow Holder the following:

            (a)  Purchase Price. The Purchase Price, less the Deposit that is
applied to the Purchase Price, plus or minus applicable prorations, deposited by
Buyer with the Escrow Holder in immediate, same-day federal funds wired for
credit into the Escrow Holder's escrow account and deposited in Escrow Holder's
escrow account.

            (b)  Assignment of Leases and Contracts and Bill of Sale. An
Assignment of Leases and Contracts and Bill of Sale executed by Buyer.

            (c)  State Law Disclosures. Such disclosures and reports as are
required by applicable state and local law in connection with the conveyance of
the Real Property.

            (d)  Wastewater Treatment Facility Documents. A Transfer Agreement,
executed by Buyer, and such other agreements and documents with respect to the
wastewater treatment facility servicing the Property as may be required by the
Massachusetts Department of Environmental Protection.

            (e)  Warranty Work Escrow Agreement. An Escrow Agreement, executed
by Buyer.

            (f)  Additional Documents. Any additional documents that Escrow
Holder or the Title Company may reasonably require for the proper consummation
of the transaction contemplated by this Agreement.

     6.3    Closing Statements/Escrow Fees; Tenant Notices. Concurrently with
the Close of Escrow, Seller and Buyer shall deposit with the Escrow Holder
executed closing statements consistent with this Agreement in the form required
by the Escrow Holder and, Seller and Buyer shall execute at the Close of Escrow,
and deliver to each tenant immediately after the Close of Escrow, tenant notices
regarding the sale of the Real Property in substantially the form of Exhibit H
attached hereto, or such other form as may be required by applicable state law.

     6.4    Post-Closing Deliveries. Immediately after the Close of Escrow, to \
the extent in Seller's possession, Seller shall deliver to the offices of
Buyer's property manager: the original Leases; copies or originals of all
warranties, contracts, receipts for deposits, and unpaid bills; all keys, if
any, used in the operation of the Real Property; and, if in Seller's possession
or control, any "as-built" plans and specifications of the Improvements; and all
other Property Information.

7.   CONDITIONS TO BUYER'S AND SELLER'S OBLIGATIONS.

     7.1    Conditions to Buyer's Obligations. The Close of Escrow and Buyer's
obligation to consummate the transaction contemplated by this Agreement are
subject to the satisfaction of the following conditions for Buyer's benefit (or
Buyer's waiver thereof, it being agreed that Buyer may waive any or all of such
conditions) on or prior to the Closing Date or on the dates designated below for
the satisfaction of such conditions:

                                      -9-

<PAGE>

            (a)  All of Seller's representations and warranties contained herein
shall be true and correct in all material respects as of the date of this
Agreement and as of the Closing Date, subject to any qualifications hereafter
made to any of Seller's representations as provided for in Section 11.1 hereof;

            (b)  As of the Closing Date, Seller shall have performed its
respective obligations hereunder and all deliveries to be made at Close of
Escrow by Seller shall have been tendered;

            (c)  There shall exist no actions, suits, arbitrations, claims,
attachments, proceedings, assignments for the benefit of creditors, insolvency,
bankruptcy, reorganization or other proceedings, pending or threatened against
Seller that would materially and adversely affect Seller's ability to perform
its respective obligations under this Agreement;

            (d)  There shall exist no pending or threatened action, suit or
proceeding with respect to Seller before or by any court or administrative
agency which seeks to restrain or prohibit, or to obtain damages or a discovery
order with respect to, this Agreement or the consummation of the transaction
contemplated hereby;

            (e)  The Title Company shall be prepared or irrevocably committed to
issue the Title Policy;

            (f)  Seller has not received service of process for any lawsuit
filed against Seller and affecting the Property, or, if Seller has received
service of process for any such lawsuit (expressly excluding any lawsuit which
arises in whole or in part from Buyer's actions), Seller shall have executed and
delivered to Buyer an indemnity agreement indemnifying Buyer from all loss that
may arise out of such lawsuit;

            (g)  Seller shall have caused the completion of all "Wastewater
Treatment Facility Work" (as hereinafter defined in this Section 7.1(g)) under
that certain Standard Form of Agreement between Owner and Contractor dated as of
August 16, 2000 between Seller, as owner, and Aberthaw Construction Company,
Inc., as contractor, in connection with the Property ("Construction Contract")
and Seller shall have caused the substantial completion of all work under the
Construction Contract which is not Wastewater Treatment Facility Work
("Non-Wastewater Treatment Facility Work"). For purposes of this Section 7.1(g)
"Wastewater Treatment Facility Work" shall mean all portions of the work to be
performed under the Construction Contract related to (i) the soil absorption
system at the Property; and (ii) all elements of the wastewaster treatment
facility at the Property over which the Massachusetts Department of
Environmental Protection and/or the Town of Boxborough Conservation Commission
have jurisdiction. For purposes of this Section 7.1(g), the Wastewater Treatment
Facility Work shall be deemed to be complete if the Massachusetts Department of
Environmental Protection has issued a certificate of compliance with respect
thereto and the Town of Boxborough Conservation Commission has issued a
conditional certificate of compliance (subject only to the stabilization of
seeded areas) with respect thereto. For purposes of this Section 7.1(g),
"substantial completion" of the Non-Wastewater Treatment Facility Work shall
mean the occurrence of the following events: (i) the completion of the
Non-Wastewater Treatment Facility Work required by the Construction Contract
(except for the Warranty Work) and (ii) Seller's architect has executed a
certificate stating that such work is so completed and which certificate
itemizes the Warranty Work; and (iii) the building permit "card" which was
issued by the Town of Boxborough in connection with the Non-Wastewater Treatment
Facility Work under the Construction Contract shall have been "signed off" by
all municipal inspectors having jurisdiction over such work;

            (h)  There shall have been no material (i.e. costs in excess of
$200,000 to remediate) releases of hazardous substances at the Property
occurring after the date of Buyer's environmental inspection of the Property;

            (i)  Seller shall have deposited in escrow, pursuant to the Escrow
Agreement, an amount equal to $300,000; and

            (j)  The Property shall be in the same condition it was in at the
expiration of the Due Diligence Period, except for any completion of Warranty
Work, reasonable wear and tear and matters governed by Section 5.4.

                                      -10-

<PAGE>

If, notwithstanding the nonsatisfaction of any such condition, the Close of
Escrow occurs, there shall be no liability on the part of Seller for breaches of
representations and warranties of which Buyer had knowledge as of the Close of
Escrow.

     7.2    Conditions to Seller's Obligations.

            The Close of Escrow and Seller's obligations to consummate the
transaction contemplated by this Agreement are subject to the satisfaction of
the following conditions for Seller's benefit (or Seller's waiver thereof, it
being agreed that Seller may waive any or all of such conditions) on or prior to
the Closing Date or the dates designated below for the satisfaction of such
conditions:

            (a)  All of Buyer's representations and warranties contained herein
shall be true and correct in all material respects as of the date of this
Agreement and as of the Closing Date subject to any qualifications made to any
of Buyer's representations as provided in Section 12 hereof ;

            (b)  As of the Closing Date, Buyer has performed its obligations
hereunder and all deliveries to be made at Close of Escrow by Buyer shall have
been tendered including, without limitation, the deposit with Escrow Holder of
the amounts set forth in Section 6.2(a) hereof;

            (c)  There shall exist no actions, suits, arbitrations, claims,
attachments, proceedings, assignments for the benefit of creditors, insolvency,
bankruptcy, reorganization or other proceedings, pending or threatened against
Buyer that would materially and adversely affect Buyer's ability to perform its
obligations under this Agreement;

            (d)  There shall exist no pending or threatened action, suit or
proceeding with respect to Buyer before or by any court or administrative agency
which seeks to restrain or prohibit, or to obtain damages or a discovery order
with respect to, this Agreement or the consummation of the transaction
contemplated hereby;

            (e)  Seller shall have received all consents and assignments and
approvals from all parties from whom such consents to assignments or approvals
are needed under all contracts, covenants and other agreements relating to the
Property;

            (f)  Seller shall have received a full general release signed by the
brokers, if any, referred to in Section 14 hereof, which shall be in form and
substance reasonably acceptable to Seller, and shall release Seller from all
costs, obligations, liabilities, commissions, fees, and claims arising from the
transaction contemplated by this Agreement upon payment of the agreed upon
commissions;

            (g)  Seller shall have received a full and complete release from
Aberthaw Construction Company, Inc. with respect to the Construction Contract
(other than with respect to the payment of the Warranty Work); and

            (h)  The sale of the property commonly known as 80 Central Street,
Boxborough, Massachusetts to 80 Central Street, LLC shall occur simultaneously
with the sale of the Property to Buyer; provided, however that if such condition
is not satisfied or waived by Seller, this Agreement shall terminate, the
Deposit shall be immediately refunded to Buyer, Buyer shall immediately return
all Property Information to Seller and, except for those provisions of this
Agreement which expressly survive the termination of this Agreement, the parties
hereto shall have no further obligations hereunder.

            8.   CLOSE OF ESCROW; POSSESSION.

     8.1    "Close of Escrow" shall mean the time the Deed is recorded with the
Middlesex South District Registry of Deeds. The Escrow (as such term is defined
in Section 9.1 hereof) and Buyer's right to purchase the Real Property will
terminate automatically (unless extended in writing by Seller and Buyer or
unless there is a

                                      -11-

<PAGE>

default by Seller referenced in Section 13.2 hereof) if the Close of Escrow does
not occur on or before 4:30 p.m. (Massachusetts time) on the Closing Date.

     8.2    Sole exclusive possession of the Real Property, subject only to the
Permitted Exceptions (as defined in Section 4.2.3 hereof), shall be delivered to
Buyer on the Closing Date.

9.   ESCROW.

     9.1    Closing. The escrow (the "Escrow") for the consummation of this
transaction shall be established with the Escrow Holder at the address indicated
in Section 15.1 hereof by the deposit of an original signed copy of this
Agreement with Escrow Holder contemporaneously with the execution hereof. This
Agreement shall constitute both an agreement among Buyer and Seller and escrow
instructions for Escrow Holder. If Escrow Holder requires separate or additional
escrow instructions which it deems necessary for its protection, Seller and
Buyer hereby agree promptly upon request by Escrow Holder to execute and deliver
to Escrow Holder such separate or additional escrow instructions (the
"Additional Instructions"). In the event of any conflict or inconsistency
between this Agreement and the Additional Instructions, this Agreement shall
prevail and govern, and the Additional Instructions shall so provide. The
Additional Instructions shall not modify or amend the provisions of this
Agreement unless otherwise agreed to in writing by Seller and Buyer.

     On the Closing Date, provided that the conditions set forth in Sections 7.1
and 7.2 hereof have been satisfied or waived, Escrow Holder shall take the
following actions in the order indicated below:

            (a)  With respect to all closing documents delivered to Escrow
Holder hereunder, and to the extent necessary, Escrow Holder is authorized to
insert into all blanks requiring the insertion of dates the date of the
recordation of the Deed or such other date as Escrow Holder may be instructed in
writing by Seller and Buyer;

            (b)  Record the Deed with the Middlesex South District Registry of
Deeds;

            (c)  Deliver to Seller, in cash or current funds, the Purchase
Price, plus or minus, as the case may be, the amounts determined in accordance
with the provisions of Section 10 hereof, Buyer's signed counterparts of the
Assignment of Leases and Contracts and Bill of Sale and conformed copies of the
recorded Deed;

            (d)  Deliver to Buyer those items referred to in Section 6.1 hereof
and a conformed copy of the recorded Deed;

            (e)  Cause the Title Company to issue the Title Policy for the Real
Property in accordance with the provisions of Section 4.2.3 hereof; and

            (f)  Deliver to Seller and Buyer a final closing statement which has
been certified by Escrow Holder to be true and correct.

     9.2    Escrow and Title Charges.

            (a)  Upon the Close of Escrow, escrow, title charges and other
closing costs shall be allocated between Seller and Buyer as follows:

                 (i)   Seller shall pay: (1) deed stamps payable in connection
with recording the Deed; (2) one-half (1/2) of any escrow fees or similar
charges of Escrow Holder, (3) all commissions payable to Seller's broker and (4)
the cost of recording any mortgage discharge documentation.

                 (ii)  Buyer shall pay (1) the premiums for the Title Policy;
(2) the cost of recording the Deed; and (3) one-half (1/2) of any escrow fees or
similar charges of Escrow Holder. If Buyer desires extended coverage for any
Title Policy, Buyer shall pay the premiums and any additional costs (including
any survey costs)

                                      -12-

<PAGE>

for such coverage (additional to the premiums for standard coverage) and the
cost of any endorsements to the Title Policy, if required by Buyer.

                 (iii) Buyer shall pay all costs incurred in connection with
Buyer's updating or recertifying the Existing Surveys or obtaining any surveys
for the Real Property.

                 (iv)  Except to the extent otherwise specifically provided
herein, all other expenses incurred by Seller and Buyer with respect to the
negotiation, documentation and closing of this transaction, including, without
limitation, Buyer's and Seller's attorneys' fees, shall be borne and paid by the
party incurring same.

            (b)  If the Close of Escrow does not occur by reason of Buyer's or
Seller's default under this Agreement, then all escrow and title charges
(including cancellation fees) shall be borne by the party in default.

     9.3    Procedures Upon Failure of Condition. Except as otherwise expressly
provided herein, if any condition set forth in Sections 7.1 or 7.2 hereof is not
timely satisfied or waived for a reason other than the default of Buyer or
Seller in the performance of its respective obligations under this Agreement:

            (a)  This Agreement, the Escrow and the respective rights and
obligations of Seller and Buyer hereunder shall terminate (other than the
indemnity and insurance obligations of Buyer set forth in Sections 4.3.1 and 14
hereof and the confidentiality provisions of Section 4.6 hereof which shall
survive such termination) at the written election of the party for whose benefit
such condition was imposed, which written election must be made (i) within three
(3) business days after the date such condition was to be satisfied, or (ii) on
the date the Close of Escrow occurs, whichever occurs first;

            (b)  Escrow Holder shall promptly return to Buyer all funds of Buyer
in its possession, including the Deposit and all interest accrued thereon, and
to Seller and Buyer all documents deposited by them respectively, which are then
held by Escrow Holder;

            (c)  Buyer shall return to Seller the Property Information and Buyer
shall deliver to Seller all Work Product (as such term is defined in Section
15.3 hereof); and

            (d)  Any escrow cancellation and title charges shall be borne
equally by Seller and Buyer.

10.  PRORATIONS.

     If the Purchase Price is deposited with Escrow Agent as required by this
Agreement, the day the Close of Escrow occurs shall belong to Buyer and all
prorations hereinafter provided to be made as of the Close of Escrow shall each
be made as of the end of the day before the Closing Date. If the cash portion of
the Purchase Price is not so received by Escrow Agent as required by this
Agreement, then the day the Close of Escrow occurs shall belong to Seller and
such proration shall be made as of the end of the day that is the Closing Date.
In each such proration set forth below, the portion thereof applicable to
periods beginning as of Close of Escrow shall be credited to Buyer or charged to
Buyer as applicable and the portion thereof applicable to periods ending as of
Close of Escrow shall be credited to Seller or charged to Seller as applicable.

     10.1   Collected Rent. All collected rent (including, without limitation,
all base rents, additional rents and retroactive rents, and expressly excluding
tenant reimbursements for Operating Costs, as hereinafter defined) and all other
collected income (and any applicable state or local tax on rent) under Leases
(hereinafter collectively referred to as "Rents") in effect on the Closing Date
shall be prorated as of the Close of Escrow. Uncollected rent and other income
shall not be prorated and, to the extent payable for the period prior to the
Close of Escrow, shall remain the property of Seller if received within six (6)
months after the Close of Escrow. Buyer shall apply Rent from tenants that are
collected within six (6) months after the Close of Escrow first to Rents which
are due to Buyer after the Close of Escrow and second to Rents which were due to
Seller on or before the Close of Escrow (to the extent such Rents were disclosed
in the Tenant Estoppel Certificates or the Rent Rolls). Any prepaid Rents for
the

                                      -13-

<PAGE>

period following the Closing Date shall be paid over by Seller to Buyer. Buyer
will make reasonable efforts, without suit, to collect any Rents applicable to
the period before the Close of Escrow including, without limitation, sending to
tenants bills for the payment of past due Rents during the first six (6) month
period following the Closing Date. Seller may pursue collection of any Rents
that were past due as of the Closing Date, provided that Seller shall have no
right to terminate any Lease or any tenant's occupancy under any Lease in
connection therewith.

     10.2   Operating Costs and Additional Rent Reconciliation. Seller, as
landlord under the Leases, is currently collecting from tenants under the Leases
additional rent to cover taxes, insurance, utilities (to the extent not paid
directly by tenants), common area maintenance and other operating costs and
expenses (collectively, "Operating Costs") in connection with the ownership,
operation, maintenance and management of the Real Property. To the extent that
any additional rent (including, without limitation, estimated payments for
Operating Costs) is paid by tenants to the landlord under the Leases based on an
estimated payment basis (monthly, quarterly, or otherwise) for which a future
reconciliation of actual Operating Costs to estimated payments is required to be
performed at the end of a reconciliation period, Buyer and Seller shall make an
adjustment at the Close of Escrow for the applicable reconciliation period (or
periods, if the Leases do not have a common reconciliation period) based on a
comparison of the actual Operating Costs to the estimated payments at the Close
of Escrow. If, as of the Close of Escrow, Seller has received additional rent
payments in excess of the amount that tenants will be required to pay, based on
the actual Operating Costs as of the Close of Escrow, Buyer shall receive a
credit in the amount of such excess. If, as of the Close of Escrow, Seller has
received additional rent payments that are less than the amount that tenants
would be required to pay based on the actual Operating Costs as of the Close of
Escrow, Seller shall be entitled to payment of such deficiency when and to the
extent Buyer receives the additional rent payments from the tenants; provided,
however, Seller shall not be entitled to the portion, if any, of such deficiency
for which Seller received a credit at the Close of Escrow under clause (b) of
Section 10.3 hereof. Operating Costs that are not payable by tenants either
directly or reimbursable under the Leases shall be prorated between Seller and
Buyer and shall be reasonably estimated by the parties if final bills are not
available.

     10.3   Taxes and Assessments. Real estate taxes and assessments imposed by
any governmental authority ("Taxes") with respect to the Real Property for the
relevant tax year in which the Real Property is being sold and that are not yet
due and payable or that have not yet been paid and that are not (and will not
be) reimbursable by tenants under the Leases (or under leases entered into after
the Close of Escrow for vacant space existing at the Close of Escrow) as
Operating Costs shall be prorated as of the Close of Escrow based upon the most
recent ascertainable assessed values and tax rates and based upon the number of
days Buyer and Seller will have owned the Real Property during such relevant tax
year. Seller shall receive a credit for any Taxes paid by Seller and applicable
to (a) any period after the Close of Escrow, and (b) any period before the Close
of Escrow to the extent reimbursable as Operating Costs by existing tenants
under the Leases and not yet received from such tenants. Additionally, Seller
shall receive a credit for any Taxes imposed with respect to the Real Property
for the relevant tax year in which the Real Property is being sold and that are
not yet due and payable or that have not yet been paid to the extent they are
capable of being reimbursed by tenants under leases that may be signed after the
Close of Escrow with respect to any vacant space in the Real Property as of the
Close of Escrow. If, as of the Closing Date, Seller is protesting or has
notified Buyer, in writing, that it has elected to protest any Taxes for the
Real Property, then Buyer agrees that Seller shall have the right (but not the
obligation), after the Closing Date, to continue such protest. In such case, any
Taxes paid by Buyer after the Closing Date with respect to the Real Property
shall be paid under protest and Buyer shall promptly notify Seller of any
payments of Taxes made by Buyer with respect to the Real Property. Buyer further
agrees to cooperate with Seller and execute any documents requested by Seller in
connection with such protest. As to the Real Property, any tax savings received
("Tax Refunds") for the relevant tax year under any protest, whether filed by
Seller or Buyer, shall be prorated between the parties based upon the number of
days, if any, Seller and Buyer respectively owned the Real Property during such
relevant tax year; if such protest was filed by a Seller, any payment of Tax
Refunds to Buyer shall be net of any fees and expenses payable to any third
party for processing such protest, including attorneys' fees. Seller shall have
the obligation to refund to any tenants in good standing as of the date of such
Tax Refund, any portion of such Tax Refund paid to Seller which may be owing to
such tenants, which payment shall be paid to Buyer within fifteen (15) business
days of delivery to Seller by Buyer of written confirmation of such tenants'
entitlement to such Tax Refunds. Buyer shall have the obligation to refund to
tenants in good standing as of the date of such Tax Refund, any portion of such
Tax Refund paid to it which may be owing to such tenants. Seller and Buyer agree
to notify the other in writing of any receipt of a Tax Refund within fifteen
(15) business days of receipt of such Tax Refund. To the extent either party
obtains a

                                      -14-

<PAGE>

Tax Refund, a portion of which is owed to the other party, the receiving party
shall deliver the Tax Refund to the other party within fifteen (15) business
days of its receipt. If Buyer or Seller fail to pay such amount(s) to the other
as and when due, such amount(s) shall bear interest from the date any such
amount is due to Seller or Buyer, as applicable, until paid at the lesser of (a)
twelve percent (12%) per annum and (b) the maximum amount permitted by law. The
obligations set forth herein shall survive the Close of Escrow and Buyer agrees
that, as a condition to the transfer of the Property by Buyer, Buyer will cause
any transferee to assume the obligations set forth herein.

     10.4   Leasing Commissions, Tenant Improvements and Service Contracts. On
or prior to the Closing, Seller shall pay all lease commission due under the
Agilent Lease with respect to the existing term of the Agilent Lease. Buyer
shall assume the obligation to pay all leasing costs (including without
limitation commissions and/or tenant improvements) with respect to renewals,
extensions or amendments to the Agilent Lease. Notwithstanding the foregoing, at
Close of Escrow, Buyer shall receive a credit in an amount equal to the Unpaid
Adjusted Agilent Tenant Improvement Allowance (as hereinafter defined in this
Section 10.4). The "Unpaid Adjusted Agilent Tenant Improvement Allowance" shall
mean that portion of the tenant allowance set forth in that certain lease dated
December 7, 2000 between Seller and Agilent Technologies, Inc. (the "Agilent
Lease"), which is Seller's responsibility, but which Seller has not paid as of
the Closing Date, less any amounts paid by Seller pursuant to change orders to
the Construction Contract which were requested by the tenant under the Agilent
Lease. Buyer will assume the obligations arising from and after the Closing Date
under the Service Contracts.

     10.5   Intentionally Omitted.

     10.6   Utilities and Utility Deposits. Utilities for the Real Property
(excluding utilities for which payment is made directly by tenants), including
water, sewer, electric, and gas, based upon the last reading of meters prior to
the Close of Escrow, shall be prorated. Seller shall be entitled to a credit for
all security deposits held by any of the utility companies providing service to
the Real Property to the extent assignable to Buyer. Seller shall endeavor to
obtain meter readings on the day before the Closing Date, and if such readings
are obtained, there shall be no proration of such items and Seller shall pay at
Close of Escrow the bills therefor for the period to the day preceding the Close
of Escrow, and Buyer shall pay the bills therefor for the period subsequent
thereto. If the utility company will not issue separate bills, Buyer will
receive a credit against the Purchase Price for Seller's portion and will pay
the entire bill prior to delinquency after Close of Escrow. If Seller has paid
utilities no more than 30 days in advance in the ordinary course of business,
then Buyer shall be charged its portion of such payment at Close of Escrow.
Buyer shall be responsible for making any security deposits required by utility
companies providing service to the Real Property.

     10.7   Owner Deposits. Seller shall receive a credit at the Close of Escrow
for all bonds, deposits, letters of credit, set aside letters or other similar
items, if any, that are outstanding with respect to the Real Property that have
been provided by Seller or any of its affiliates to any governmental agency,
public utility, or similar entity (collectively, "Owner Deposits") to the extent
assignable to Buyer. To the extent any Owner Deposits are not assignable to
Buyer, Buyer shall replace such Owner Deposits and obtain the release of Seller
(or its affiliates) from any obligations under such Owner Deposits. To the
extent that any funds are released as a result of the termination of any Owner
Deposits for which Seller did not get a credit, such funds shall be delivered to
Seller immediately upon their receipt.

     10.8   Final Adjustment After Closing. If final prorations cannot be made
at the Close of Escrow for any item being prorated under this Section 10, then
Buyer and Seller agree to allocate such items on a fair and equitable basis as
soon as invoices or bills are available and applicable reconciliation with
tenants have been completed, with final adjustment to be made as soon as
reasonably possible after the Close of Escrow (but in no event later than
forty-five (45) days after the Close of Escrow, except that adjustments arising
from Section 10.3 shall not be subject to such 45 day limitation, but shall be
made as soon as reasonably possible), to the effect that income and expenses are
received and paid by the parties on an accrual basis with respect to their
period of ownership. Payments in connection with the final adjustment shall be
due no later than forty-five (45) days after the Close of Escrow, except that
adjustments arising from Section 10.3 shall not be subject to such 45 day
limitation, but shall be made as soon as reasonably possible. Seller shall, at
Seller's sole cost and expense, have reasonable access to, and the right to
inspect and audit, Buyer's books to confirm the final prorations for a period of
one (1) year after the Close of Escrow. Such information will be treated by
Seller, its affiliates, lenders, employees and

                                      -15-

<PAGE>

agents as confidential, and will not be disclosed to anyone except to Seller's
consultants who agree to maintain the confidentiality of such information.

     10.9   No Marketing of Property. During the pendency of this Agreement,
Seller agrees that it shall not market the Property for sale to any other party.

11.  SELLER'S REPRESENTATIONS AND WARRANTIES; AS-IS.

     11.1   Seller's Representations and Warranties. In consideration of Buyer's
entering into this Agreement and as an inducement to Buyer to purchase the Real
Property from Seller, Seller makes the following representations and warranties
to Buyer:

            (a)  Seller has the legal right, power and authority to enter into
this Agreement and to consummate the transactions contemplated hereby, and the
execution, delivery and performance of this Agreement have been duly authorized
and no other action by Seller is requisite to the valid and binding execution,
delivery and performance of this Agreement, except as otherwise expressly set
forth herein.

            (b)  There is no agreement to which Seller is a party or to Seller's
Actual Knowledge binding on Seller which is in conflict with this Agreement.

            (c)  To Seller's Actual Knowledge, Seller has not received written
notice by any governmental body of (i) any pending or threatened condemnation
proceeding that would affect the Real Property, or (ii) the violation by the
Real Property of any building, fire, health, use, occupancy, environmental or
zoning regulations that has not been cured.

            (d)  To Seller's Actual Knowledge, Seller has not been served with a
complaint or other papers disclosing the filing of a lawsuit against Seller with
respect to the Real Property, except as disclosed in Schedule 4 attached hereto.

            (e)  To Seller's Actual Knowledge, except as disclosed on Schedule 2
attached hereto and made a part hereof, Seller has not entered into any lease
brokerage agreements, leasing commission agreements or other agreements which
will survive the Closing and which provide for the payment of any amounts for
leasing space in the Property or procuring tenants with respect to the Property
(the "Commission Agreements").

            (f)  To Seller's Actual Knowledge, Seller has made available to
Buyer all material documents in Seller's possession or control with respect to
the Property at Seller's address set forth in Section 15.1 or at the offices of
Insignia/ESG, Inc., 10 Post Office Square, Boston, Massachusetts, or at the
offices of Spaulding & Slye Colliers, 255 State Street, Boston, Massachusetts,
or at the offices of CB Richard Ellis, 80-90 Central Street, Boxborough,
Massachusetts.

            (g)  To Seller's Actual Knowledge, none of the tenant under the
Leases are in monetary default.

            (h)  The scheduled closing date for the sale of the property
commonly known as 80 Central Street, Boxborough, Massachusetts to 80 Central
Street, LLC is April 18, 2002.

For purposes of this Section 11.1, the phrase "To Seller's Actual Knowledge"
shall mean the actual (and not implied, imputed, or constructive) knowledge of
David S. Hall (whom Seller represents is the person generally responsible for
the management and operation of the Property), without any inquiry or
investigation of any other parties, including, without limitation, the tenants
and the property manager of the Real Property.

The representations and warranties made by Seller in this Agreement shall
survive the recordation of the Deed for a period of one (1) year and any action
for a breach of Seller's representations or warranties must be made and filed
within said one (1) year period. If, after the Effective Date, but before the
Close of Escrow, Seller becomes aware of

                                      -16-

<PAGE>

any facts or changes in circumstances that would cause any of its
representations and warranties in this Agreement to be untrue at Close of
Escrow, Seller shall promptly notify Buyer in writing of such fact. In such
case, or in the event Buyer obtains information which would cause any of
Seller's representations and warranties to be untrue at Close of Escrow, Buyer,
as its sole and exclusive remedy, shall have the right to either (i) terminate
this Agreement, in which case the Deposit shall be immediately returned to Buyer
and neither party shall have any rights or obligations under this Agreement
(except for Sections 4.3.1, 15.3 and 15.5 which survive termination of this
Agreement); or (ii) accept a qualification to Seller's representations and
warranties as of the Close of Escrow and complete the purchase and sale of the
Property without any rights to recovery for breach of the unqualified
representation and warranty. Other than as set forth in the immediately
preceding sentence, if Buyer proceeds with the Close of Escrow, Buyer shall be
deemed to have expressly waived any and all remedies for the breach of any
representation or warranty discovered by Buyer prior to the Close of Escrow.

     11.2   As-Is. As of the expiration of the Due Diligence Period, Buyer will
have:

            (a)  examined and inspected the Property and will know and be
satisfied with the physical condition, quality, quantity and state of repair of
the Property in all respects (including, without limitation, the compliance of
the Real Property with the Americans With Disabilities Act of 1990 Pub.L.
101-336, 104 Stat. 327 (1990), and any comparable local or state laws
(collectively, the "ADA") and by proceeding with this transaction following the
expiration of the Due Diligence Period shall be deemed to have determined that
the same is satisfactory to Borrower;

            (b)  reviewed the Property Information and all instruments, records
and documents which Buyer deems appropriate or advisable to review in connection
with this transaction, including, but not by way of limitation, any and all
architectural drawings, plans, specifications, surveys, building and occupancy
permits, and any licenses, leases, contracts, warranties and guarantees relating
to the Real Property or the business conducted thereon, and Buyer, by proceeding
with this transaction following the expiration of the Due Diligence Period,
shall be deemed to have determined that the same and the information and data
contained therein and evidenced thereby are satisfactory to Buyer;

            (c)  reviewed all applicable laws, ordinances, rules and
governmental regulations (including, but not limited to, those relating to
building, zoning and land use) affecting the development, use, occupancy or
enjoyment of the Real Property, and Buyer, by proceeding with this transaction
following the expiration of the Due Diligence Period, shall be deemed to have
determined that the same are satisfactory to Buyer; and

            (d)  at its own cost and expense, made its own independent
investigation respecting the Property and all other aspects of this transaction,
and shall have relied thereon and on the advice of its consultants in entering
into this Agreement, and Buyer, by proceeding with this transaction following
the expiration of the Due Diligence Period, shall be deemed to have determined
that the same are satisfactory to Buyer.

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, AND EXCEPT FOR SELLER'S
REPRESENTATIONS AND WARRANTIES IN SECTION 11.1 OF THIS AGREEMENT AND ANY
WARRANTIES OF TITLE CONTAINED IN THE DEED DELIVERED AT THE CLOSE OF ESCROW
("SELLER'S WARRANTIES"), THIS SALE IS MADE AND WILL BE MADE WITHOUT
REPRESENTATION, COVENANT, OR WARRANTY OF ANY KIND (WHETHER EXPRESS, IMPLIED, OR,
TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, STATUTORY) BY SELLER. AS A
MATERIAL PART OF THE CONSIDERATION FOR THIS AGREEMENT, BUYER AGREES TO ACCEPT
THE PROPERTY ON AN "AS IS" AND "WHERE IS" BASIS, WITH ALL FAULTS, AND WITHOUT
ANY REPRESENTATION OR WARRANTY, ALL OF WHICH SELLER HEREBY DISCLAIMS, EXCEPT FOR
SELLER'S WARRANTIES. EXCEPT FOR SELLER'S WARRANTIES, NO WARRANTY OR
REPRESENTATION IS MADE BY SELLER AS TO FITNESS FOR ANY PARTICULAR PURPOSE,
MERCHANTABILITY, DESIGN, QUALITY, CONDITION, OPERATION OR INCOME, COMPLIANCE
WITH DRAWINGS OR SPECIFICATIONS, ABSENCE OF DEFECTS, ABSENCE OF HAZARDOUS OR
TOXIC SUBSTANCES, ABSENCE OF FAULTS, FLOODING, OR COMPLIANCE WITH LAWS AND
REGULATIONS INCLUDING, WITHOUT LIMITATION, THOSE RELATING TO HEALTH, SAFETY, AND
THE ENVIRONMENT (INCLUDING, WITHOUT LIMITATION, THE ADA). BUYER ACKNOWLEDGES
THAT BUYER HAS ENTERED INTO THIS

                                      -17-

<PAGE>

AGREEMENT WITH THE INTENTION OF MAKING AND RELYING UPON ITS OWN INVESTIGATION OF
THE PHYSICAL, ENVIRONMENTAL, ECONOMIC USE, COMPLIANCE, AND LEGAL CONDITION OF
THE PROPERTY AND THAT BUYER IS NOT NOW RELYING, AND WILL NOT LATER RELY, UPON
ANY REPRESENTATIONS AND WARRANTIES MADE BY SELLER OR ANYONE ACTING OR CLAIMING
TO ACT, BY, THROUGH OR UNDER OR ON SELLER'S BEHALF CONCERNING THE PROPERTY.
ADDITIONALLY, BUYER AND SELLER HEREBY AGREE THAT (A) EXCEPT FOR SELLER'S
WARRANTIES, BUYER IS TAKING THE PROPERTY "AS IS" WITH ALL LATENT AND PATENT
DEFECTS AND THAT EXCEPT FOR SELLER'S WARRANTIES, THERE IS NO WARRANTY BY SELLER
THAT THE PROPERTY IS FIT FOR A PARTICULAR PURPOSE, (B) EXCEPT FOR SELLER'S
WARRANTIES, BUYER IS SOLELY RELYING UPON ITS EXAMINATION OF THE PROPERTY, AND
(C) BUYER TAKES THE PROPERTY UNDER THIS CONTRACT UNDER THE EXPRESS UNDERSTANDING
THAT THERE ARE NO EXPRESS OR IMPLIED WARRANTIES (EXCEPT FOR THE LIMITED
WARRANTIES OF TITLE SET FORTH IN THE DEED AND SELLER'S WARRANTIES).

WITH RESPECT TO THE FOLLOWING, BUYER FURTHER ACKNOWLEDGES AND AGREES THAT EXCEPT
AS EXPRESSLY SET FORTH IN THIS AGREEMENT, SELLER SHALL NOT HAVE ANY LIABILITY,
OBLIGATION OR RESPONSIBILITY OF ANY KIND AND THAT SELLER HAS MADE NO
REPRESENTATIONS OR WARRANTIES OF ANY KIND:

1.   THE CONTENT OR ACCURACY OF ANY REPORT, STUDY, OPINION OR CONCLUSION OF ANY
     SOILS, TOXIC, ENVIRONMENTAL OR OTHER ENGINEER OR OTHER PERSON OR ENTITY WHO
     HAS EXAMINED THE PROPERTY OR ANY ASPECT THEREOF;

2.   THE CONTENT OR ACCURACY OF ANY OF THE ITEMS (INCLUDING, WITHOUT LIMITATION,
     THE PROPERTY INFORMATION) DELIVERED TO BUYER PURSUANT TO BUYER'S REVIEW OF
     THE CONDITION OF THE PROPERTY; OR

3.   THE CONTENT OR ACCURACY OF ANY PROJECTION, FINANCIAL OR MARKETING ANALYSIS
     OR OTHER INFORMATION GIVEN TO BUYER BY SELLER OR REVIEWED BY BUYER WITH
     RESPECT TO THE PROPERTY.

BUYER ALSO ACKNOWLEDGES THAT THE REAL PROPERTY MAY OR MAY NOT CONTAIN ASBESTOS
AND, IF THE REAL PROPERTY CONTAINS ASBESTOS, THAT BUYER MAY OR MAY NOT BE
REQUIRED TO REMEDIATE ANY ASBESTOS CONDITION IN ACCORDANCE WITH APPLICABLE LAW.

BUYER IS A SOPHISTICATED REAL ESTATE INVESTOR AND IS, OR WILL BE AS OF THE CLOSE
OF ESCROW, FAMILIAR WITH THE REAL PROPERTY AND ITS SUITABILITY FOR BUYER'S
INTENDED USE. THE PROVISIONS OF THIS SECTION 11.2 SHALL SURVIVE INDEFINITELY ANY
CLOSING OR TERMINATION OF THIS AGREEMENT AND SHALL NOT BE MERGED INTO THE
DOCUMENTS EXECUTED AT CLOSE OF ESCROW.

                                                             WLO
                                                            --------------------
                                                            BUYER'S INITIALS

12.  BUYER'S COVENANTS, REPRESENTATIONS AND WARRANTIES; RELEASE; ERISA.

     In consideration of Seller entering into this Agreement and as an
inducement to Seller to sell the Real Property to Buyer, Buyer makes the
following covenants, representations and warranties:

     12.1   Authority. Buyer has the legal right, power and authority to enter
into this Agreement and to consummate the transactions contemplated hereby, and
the execution, delivery and performance of this Agreement have been duly
authorized and no other action by Buyer is requisite to the valid and binding
execution, delivery and performance of this Agreement, except as otherwise
expressly set forth herein. There is no agreement to which

                                      -18-

<PAGE>

Buyer is a party or to Buyer's actual knowledge (which shall be limited to the
actual knowledge without inquiry or investigation (and not implied, imputed, or
constructive knowledge) of L. Clay Adams, Jr.) binding on Buyer which is in
conflict with this Agreement.

     12.2  Release. By proceeding with this transaction following the expiration
of the Due Diligence Period, Buyer shall be deemed to have made its own
independent investigation of the Property, the Property Information and the
presence of Hazardous Materials on the Real Property as Buyer deems appropriate.
Accordingly, subject to the representations and warranties of Seller expressly
set forth in Section 11.1 hereof, Buyer, on behalf of itself and all of its
officers, directors, shareholders, employees, representatives and affiliated
entities (collectively, the "Releasors") hereby expressly waives and
relinquishes any and all rights and remedies Releasors may now or hereafter have
against Seller, its successors and assigns, trustees, beneficiaries, officers,
directors, members, representatives, principals, partners, shareholders,
employees and/or agents (the "Seller Parties"), whether known or unknown, which
may arise from or be related to (a) the physical condition, quality, quantity
and state of repair of the Real Property and the prior management and operation
of the Real Property, (b) the Property Information, (c) the Real Property's
compliance or lack of compliance with any federal, state or local laws or
regulations, and (d) any past, present or future presence or existence of
Hazardous Materials on, under or about the Real Property or with respect to any
past, present or future violation of any rules, regulations or laws, now or
hereafter enacted, regulating or governing the use, handling, storage or
disposal of Hazardous Materials, including, without limitation, (i) any and all
rights and remedies Releasors may now or hereafter have under the Comprehensive
Environmental Response Compensation and Liability Act of 1980 ("CERCLA"), the
Superfund Amendments and Reauthorization Act of 1986, the Resource Conservation
and Recovery Act, and the Toxic Substance Control Act, all as amended, and any
similar state, local or federal environmental law, rule or regulation, (ii) any
and all claims, whether known or unknown, now or hereafter existing, with
respect to the Real Property under Section 107 of CERCLA (42 U.S.C.A. ss.9607)
and (iii) any and all rights, remedies and claims, whether known or unknown, now
or hereafter existing, with respect to the Real Property under Massachusetts
General Laws, Chapter 21C and/or Massachusetts General Laws, Chapter 21E. As
used herein, the term "Hazardous Material(s)" includes, without limitation, any
hazardous or toxic materials, substances or wastes, such as (1) any materials,
substances or wastes which are toxic, ignitable, corrosive or reactive and which
are regulated by any local governmental authority, or any agency of the United
States government, (2) any other material, substance, or waste which is defined
or regulated as a hazardous material, extremely hazardous material, hazardous
waste or toxic substance pursuant to any laws, rules, regulations or orders of
the United States government, or any local governmental body, (3) asbestos, (4)
petroleum and petroleum based products, (5) formaldehyde, (6) polychlorinated
biphenyls (PCBs), and (7) freon and other chlorofluorocarbons.

     Seller and Buyer agree and acknowledge that the foregoing release shall not
apply to claims arising from third party claims asserted against Buyer arising
from environmental contamination of (i) the Property (other than environmental
contamination on the Property on March 13, 2002) and (ii) properties abutting
the Property, which contamination, in all cases, was due to occurrences
happening during Seller's ownership of the Property; provided, however that
Buyer only shall be entitled to such actual changes (and not consequential as
other special damages) in connection therewith.

WITHOUT LIMITING SELLER'S REPRESENTATIONS AND WARRANTIES SET FORTH IN THIS
AGREEMENT, BUYER, ON BEHALF OF ITSELF AND THE OTHER RELEASORS, HEREBY ASSUMES
ALL RISK AND LIABILITY RESULTING OR ARISING FROM, OR RELATING TO THE OWNERSHIP,
USE, CONDITION, LOCATION, MAINTENANCE, REPAIR, OR OPERATION OF, THE PROPERTY.

                                      -19-

<PAGE>

     THE FOREGOING WAIVERS, RELEASES AND AGREEMENTS BY BUYER, ON BEHALF OF
ITSELF AND THE RELEASORS, SHALL SURVIVE THE CLOSE OF ESCROW AND THE RECORDATION
OF THE DEED AND SHALL NOT BE DEEMED MERGED INTO THE DEED UPON ITS RECORDATION.

     12.3  ERISA. Buyer is not purchasing any of the Property with "plan assets"
of an Employee Benefit Plan subject to Title I of the Employee Retirement Income
Security Act of 1974 (as amended from time to time, the "Act," and together with
any regulation, rule or judicial or administrative case, order, or pronouncement
arising under or connected with the Act, "ERISA") or of a plan subject to
Section 4975 of the Internal Revenue Code of 1986, as amended (the "Code"). In
the event that this Agreement, or any transaction or other action by Seller in
connection herewith, shall be deemed to violate ERISA or result in an imposition
of an excise tax under Section 4975 of the Code, Seller may immediately
terminate this Agreement (without any liability to Seller) in accordance with,
and subject to the terms and conditions of, Section 9.3 hereof as if such
termination arose from a failed condition under Section 9.3 hereof.

     12.4  Warranty Work. Buyer agrees and acknowledges that Seller's liability
with respect to the performance of the Warranty Work, including without
limitation any failure to perform the Warranty Work or the improper performance
of the Warranty Work, is limited to Buyer's rights and remedies under the Escrow
Agreement, which rights and remedies are Buyer's sole rights and remedies in
connection therewith, at law or in equity. The provisions of this Section 12.4
shall survive the Closing.

13.  DEFAULT AND DAMAGES.

     13.1  DEFAULT BY BUYER. BUYER AND SELLER HEREBY ACKNOWLEDGE AND AGREE THAT,
IN THE EVENT THE CLOSE OF ESCROW FAILS TO OCCUR DUE TO A BUYER DEFAULT (ALL OF
THE CONDITIONS TO BUYER'S OBLIGATIONS TO CLOSE HAVING BEEN SATISFIED OR WAIVED),
SELLER WILL SUFFER DAMAGES IN AN AMOUNT WHICH WILL, DUE TO THE SPECIAL NATURE OF
THE TRANSACTION CONTEMPLATED BY THIS AGREEMENT AND THE SPECIAL NATURE OF THE
NEGOTIATIONS WHICH PRECEDED THIS AGREEMENT, BE IMPRACTICAL OR EXTREMELY
DIFFICULT TO ASCERTAIN. IN ADDITION, BUYER WISHES TO HAVE A LIMITATION PLACED
UPON THE POTENTIAL LIABILITY OF BUYER TO SELLER IN THE EVENT THE CLOSE OF ESCROW
FAILS TO OCCUR DUE TO A BUYER DEFAULT, AND WISHES TO INDUCE SELLER TO WAIVE
OTHER REMEDIES WHICH SELLER MAY HAVE IN THE EVENT OF A BUYER DEFAULT. BUYER AND
SELLER, AFTER DUE NEGOTIATION, HEREBY ACKNOWLEDGE AND AGREE THAT THE AMOUNT OF
THE DEPOSIT REPRESENTS A REASONABLE ESTIMATE OF THE DAMAGES WHICH SELLER WILL
SUSTAIN IN THE EVENT OF SUCH BUYER DEFAULT. BUYER AND SELLER HEREBY AGREE THAT
SELLER MAY, IN THE EVENT THE CLOSE OF ESCROW FAILS TO OCCUR DUE TO A BUYER
DEFAULT, TERMINATE THIS AGREEMENT BY WRITTEN NOTICE TO BUYER AND ESCROW HOLDER,
CANCEL THE ESCROW AND RECEIVE THE DEPOSIT AS LIQUIDATED DAMAGES AND ESCROW
HOLDER SHALL IMMEDIATELY DELIVER THE DEPOSIT TO SELLER. SUCH RETENTION OF THE
DEPOSIT BY SELLER IS INTENDED TO CONSTITUTE LIQUIDATED DAMAGES TO SELLER AND
SHALL NOT BE DEEMED TO CONSTITUTE A FOREFEITURE OR PENALTY.

     NOTHING IN THIS SECTION 13.1 SHALL (A) PREVENT OR PRECLUDE ANY RECOVERY OF
ATTORNEYS' FEES OR OTHER COSTS INCURRED BY SELLER PURSUANT TO SECTION 15.5 OR
(B) IMPAIR OR LIMIT THE EFFECTIVENESS OR ENFORCEABILITY OF THE INDEMNIFICATION
OBLIGATIONS OF BUYER CONTAINED IN SECTIONS 4.3.1 AND 14 HEREOF. SELLER AND BUYER
ACKNOWLEDGE THAT THEY HAVE READ AND UNDERSTAND THE PROVISIONS OF THIS SECTION
13.1 AND BY THEIR INITIALS IMMEDIATELY BELOW AGREE TO BE BOUND BY ITS TERMS.

                                                            Seller's Initials:
                                                            _____________
                                                            Buyer's Initials:
                                                            WLO
                                                            -------------

                                      -20-

<PAGE>

     13.2  Default by Seller. If Seller defaults in its obligations to sell and
convey the Property to Buyer pursuant to this Agreement, Buyer's sole and
exclusive remedy shall be to elect one of the following: (a) to receive the
return of the Deposit and up to Fifty Thousand Dollars ($50,000) of Buyer's
legal and third party costs and expenses incurred in connection with this
transaction and Buyer's due diligence of the Property, which return shall
operate to terminate this Agreement and release Seller from any and all
liability hereunder, or (b) to bring a suit for specific performance provided
that any suit for specific performance must be brought as to the Property within
30 days of Seller's default, Buyer's waiving the right to bring suit at any
later date to the extent permitted by law. This Agreement confers no present
right, title or interest in the Property to Buyer and Buyer agrees not to file a
lis pendens or other similar notice against the Real Property except in
connection with, and after, the proper filing of a suit for specific
performance.

14.  BROKER'S COMMISSIONS.

     Except for the Royston Group and Insignia/ESG, Inc., Seller's broker (each
of whose commissions shall be paid by Seller pursuant to separate agreements,
neither party hereto has had any contact or dealing regarding the Real Property,
or any communication in connection with the subject matter of this transaction,
through any licensed real estate broker or other person who can claim a right to
a commission or finder's fee as a procuring cause of the sale contemplated
herein. In the event that any other broker or finder perfects a claim for a
commission or finder's fee, the party responsible for the contact or
communication on which the broker or finder perfected such claim shall
indemnify, save harmless and defend the other party from said claim and all
costs and expenses (including reasonable attorneys' fees) incurred by the other
party in defending against the same.

15.  MISCELLANEOUS PROVISIONS.

     15.1  Notices. All written notices or demands of any kind which either
party hereto may be required or may desire to serve on the other in connection
with this Agreement shall be served by personal service, by registered or
certified mail, recognized overnight courier service or facsimile transmission.
Any such notice or demand so to be served by registered or certified mail,
recognized overnight courier service or facsimile transmission shall be
delivered with all applicable delivery charges thereon fully prepaid and, if the
party so to be served be Buyer, addressed to Buyer as follows:

                           c/o Wells Capital, Inc.
                           6200 The Corners Parkway, Suite 250
                           Norcross, Georgia  30092
                           Attention: L. Clay Adams, Jr.
                           Telephone No.: (770) 243-8439
                           Fax No.: (770) 243-8510


with a copy thereof to:

                           O'Callaghan & Stumm LLP
                           127 Peachtree Street, N.E., Suite 1330
                           Atlanta, Georgia  30303
                           Attention.: William L. O'Callaghan, Jr., Esquire
                           Telephone No.: (404) 522-2002
                           Fax No.: (404) 522-3080

                                      -21-

<PAGE>

and, if the party so to be served be Seller, addressed to Seller as follows:

                           c/o Koll Bren Schreiber Realty Advisors, Inc.
                           125 Summer Street, Suite 1640
                           Boston, MA 02110
                           Attention: David S. Hall
                           Telephone No.: (617) 345-0600 x106
                           Fax No.: (617) 345-9200

with copies thereof to:

                           James Chiboucas, Esquire
                           4343 Von Karman Avenue
                           Newport Beach, CA 92660
                           Telephone No.: (949) 833-3030, Ext. 398
                           Fax No.: (949) 852-9472

                           and

                           Edward S. Hershfield, Esquire
                           Brown Rudnick Berlack Israels LLP
                           One Financial Center
                           Boston, MA 02111
                           Telephone No.: (617) 856-8545
                           Fax No.: (617) 856-8201


and, if the party to be served be Escrow Holder, addressed to Escrow Holder as
follows:

                           Chicago Title Insurance Company
                           16969 Von Karman, Suite 200
                           Irvine, California 92606
                           Attention: Ms. Joy Eaton
                           Telephone No.: (949) 263-0123
                           Fax No.: (949) 263-0356

Service of any such notice or demand so made by personal delivery, registered or
certified mail, recognized overnight courier or facsimile transmission shall be
deemed complete on the date of actual delivery as shown by the addressee's
registry or certification receipt or, as to facsimile transmissions, by "answer
back confirmation" (provided that a copy of such notice or demand is delivered
by any of the other methods provided above within one (1) business day following
receipt of such facsimile transmission), as applicable, or at the expiration of
the third (3rd) business day after the date of dispatch, whichever is earlier in
time. Either party hereto may from time to time, by notice in writing served
upon the other as aforesaid, designate a different mailing address to which or a
different person to whose attention all such notices or demands are thereafter
to be addressed.

     15.2  Assignment; Binding on Successors and Assigns. Buyer shall not
assign, transfer or convey its rights or obligations under this Agreement or
with respect to the Property without the prior written consent of Seller, which
consent Seller may withhold in its sole, absolute and subjective discretion;
provided, however, Buyer may assign its rights hereunder to an affiliated entity
so long as (a) Buyer provides Seller with no less than five (5) days prior
written notice of such intended assignment, (b) the assignee assumes Buyer's
obligations under this Agreement pursuant to an assignment and assumption
agreement acceptable to Seller, and (c) Buyer shall not be released from its
obligations hereunder. Any attempted assignment in violation of the provisions
of this Section 15.2 shall be void and Buyer shall be deemed in default
hereunder. Any permitted assignments shall not relieve the assigning party from
its liability under this Agreement. Subject to the foregoing, and except as
provided to the contrary herein, the terms, covenants, conditions and warranties
contained herein and the powers granted hereby shall inure to the

                                      -22-

<PAGE>

benefit of and bind all parties hereto and their respective heirs, executors,
administrators, successors and assigns, and all subsequent owners of the
Property.

     15.3  Work Product. Effective upon and in the event of a termination of
this Agreement for any reason (other than due to a Seller default), Buyer shall
assign and deliver to Seller (at no cost to Seller and without any
representations or warranties by Buyer), and does hereby assign without the need
for any further act or instrument (at no cost to Seller), copies of all reports,
plans, studies, documents, written information and the like (but expressly
excluding any market and feasibility studies, any appraisals and any internal
financial audits or reports relating to the Property) which has been generated
by Buyer's third party consultants (excluding Buyer's attorneys), whether prior
to the Opening of Escrow or during the period of Escrow in connection with
Buyer's proposed acquisition, development, use or sale of the Real Property
(collectively, the "Work Product"). In such event, Buyer shall deliver the Work
Product which has been assigned to Seller not later than ten (10) days after the
date of the termination of this Agreement. The Work Product shall be fully paid
for and shall not be subject to any lien, encumbrance or claim of any kind.
Buyer shall also return all materials and information (including, without
limitation, the Property Information) given to it by Seller or its consultants
during Escrow, in the same condition as delivered to Buyer. Buyer shall be
entitled to retain a copy of the foregoing materials and information provided
Seller incurs no cost or expense in connection therewith.

     15.4  Further Assurances; Completion of Warranty Work. In addition to the
acts and deeds recited herein and contemplated to be performed, executed or
delivered by Seller or Buyer, Seller and Buyer hereby agree to perform, execute
and deliver, or cause to be performed, executed and delivered, on the Closing
Date or thereafter any and all such further acts, deeds and assurances as Buyer
or Seller, as the case may be, may reasonably require in order to consummate
fully the transactions contemplated hereunder.

     Without limiting the generality of the foregoing, Buyer agrees to cooperate
with Seller, Seller's agents, architects and contractors following the Close of
Escrow, including, without limitation, granting Seller and such third parties
access to the Property, so as to enable Seller and such third parties to
complete the Warranty Work as contemplated in the Escrow Agreement.

     15.5  Attorneys' Fees. If any legal action or any arbitration or other
proceeding is brought or if an attorney is retained for the enforcement of this
Agreement or any portion thereof, or because of any alleged dispute, breach,
default or misrepresentation in connection with any of the provisions of this
Agreement, the prevailing party shall be entitled to recover from the other
reimbursement for the reasonable fees of attorneys and other costs (including
court costs and witness fees) incurred by it, in addition to any other relief to
which it may be entitled. The term "prevailing party" means the party obtaining
substantially the relief sought, whether by compromise, settlement or judgment.

     15.6  Survival of Representations, Warranties and Agreements. Unless
otherwise expressly stated in this Agreement (a) each of the covenants,
obligations, representations, and agreements contained in this Agreement shall
survive the Close of Escrow and the execution and delivery of the Deed only for
a period of one (1) year immediately following the Closing Date, and (b) any
claim based upon a misrepresentation or a breach of a warranty contained in this
Agreement shall be actionable or enforceable if and only if notice of such claim
is given to the party which allegedly made such misrepresentation or breached
such covenant, obligation, warranty or agreement within one (1) year after the
Closing Date; provided, however, in no event shall Seller's liability, if any,
with respect to any breach of Seller's representations or warranties hereunder
exceed $500,000 in the aggregate. Notwithstanding anything stated to the
contrary in this Agreement, the indemnification provisions of Sections 4.3.1,
10.5, 14 and 15.14 hereof and the provisions of Sections 4.6, 10.1, 10.3, 10.8,
11.1, 11.2, 12.1, 12.2, 12.3, 12.4, 13.2, 15.3, 15.4, 15.5, 15.17, 15.20 and
15.23 hereof shall survive the termination of this Agreement or the Close of
Escrow without limitation, and shall not be merged with the recording of the
Deed.

     15.7  Entire Agreement. This Agreement contains the entire agreement and
understanding of the parties in respect to the subject matter hereof, and the
parties intend for the literal words of this Agreement to govern and for all
prior negotiations, drafts, and other extrinsic communications, whether oral or
written, to have no significance or evidentiary effect. The parties further
intend that neither this Agreement nor any of its provisions may be changed,
amended, discharged, waived or otherwise modified orally except only by an
instrument in writing

                                      -23-

<PAGE>

duly executed by the party to be bound thereby. The parties hereto fully
understand and acknowledge the importance of the foregoing sentence and are
aware that the law may permit subsequent oral modification of a contract
notwithstanding contract language which requires that any such modification be
in writing; but Buyer and Seller fully and expressly intend that the foregoing
requirements as to a writing be strictly adhered to and strictly interpreted and
enforced by any court which may be asked to decide the question. Each party
hereto acknowledges that this Agreement accurately reflect the agreements and
understandings of the parties hereto with respect to the subject matter hereof
and hereby waive any claim against the other party which such party may now have
or may hereafter acquire to the effect that the actual agreements and
understandings of the parties hereto with respect to the subject matter hereof
may not be accurately set forth in this Agreement.

     15.8  Governing Law. This Agreement shall be governed by the laws of the
Commonwealth of Massachusetts.

     15.9  Counterparts. This Agreement may be executed simultaneously in one or
more counterparts, each of which shall be deemed an original but all of which
together shall constitute one and the same instrument.

     15.10 Headings; Construction. The various headings of this Agreement are
included for convenience only and shall not affect the meaning or interpretation
of this Agreement or any provision hereof. When the context and construction so
require, all words used in the singular herein shall be deemed to have been used
in the plural and the masculine shall include the feminine and the neuter and
vice versa. The use in this Agreement of the term "including" and related terms
such as "include" shall in all cases mean "without limitation." All references
to "days" in this Agreement shall be construed to mean calendar days unless
otherwise expressly provided and all references to "business days" shall be
construed to mean days on which national banks are open for business in
Massachusetts.

     15.11 Time of Essence. Seller and Buyer hereby acknowledge and agree that
time is strictly of the essence with respect to each and every term, condition,
obligation and provision hereof and failure to perform timely any of the terms,
conditions, obligations or provisions hereof by either party shall constitute a
material breach of, and non-curable (but waivable) default under this Agreement
by the parties so failing to perform.

     15.12 Partial Validity; Severability. If any term or provision of this
Agreement or the application thereof to any person or circumstance shall, to any
extent, be held invalid or unenforceable, 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, and each such term and provision of this Agreement shall be valid and
be enforced to the fullest extent permitted by law.

     15.13 No Third Party Beneficiaries. This Agreement is for the sole and
exclusive benefit of the parties hereto and their respective permitted
successors and assigns, and no third party is intended to, or shall have, any
rights hereunder.

     15.14 Recordation of Agreement. Neither Seller nor Buyer may record the
Agreement or any notice of this Agreement. To the extent that any such filing is
made by Buyer in violation of this Agreement, Buyer shall indemnify Seller
against any damages incurred by Seller in connection therewith. The provisions
of this Section 15.14 shall survive the termination of this Agreement.

     15.15 Joint Product of Parties. This Agreement is the result of arms-length
negotiations between Seller and Buyer and their respective attorneys.
Accordingly, neither party shall be deemed to be the author of this Agreement
and this Agreement shall not be construed against either party.

     15.16 Calculation of Time Periods. Unless otherwise specified, in computing
any period of time described herein, 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 so computed is to be included at, unless such last day is a
Saturday, Sunday or legal holiday for national banks in Massachusetts, in which
event the period shall run until the end of the next

                                      -24-

<PAGE>

day which is neither a Saturday, Sunday, or legal holiday. Unless otherwise
expressly provided herein, the last day of any period of time described herein
shall be deemed to end at 5:00 p.m., Massachusetts time.

     15.17 Procedure for Indemnity. The following provisions govern actions for
indemnity under this Agreement. Promptly after receipt by an indemnitee of
notice of any claim, such indemnitee will, if a claim in respect thereof is to
be made against the indemnitor, deliver to the indemnitor written notice thereof
and the indemnitor shall have the right to participate in and, if the indemnitor
agrees in writing that it will be responsible for any costs, expenses,
judgments, damages, and losses incurred by the indemnitee with respect to such
claim, to assume the defense thereof, with counsel mutually satisfactory to the
parties; provided, however, that an indemnitee shall have the right to retain
its own counsel, with the fees and expenses to be paid by the indemnitor, if the
indemnitee reasonably believes that representation of such indemnitee by the
counsel retained by the indemnitor would be inappropriate due to actual or
potential differing interests between such indemnitee and any other party
represented by such counsel in such proceeding. The failure of indemnitee to
deliver written notice to the indemnitor within a reasonable time after
indemnitee receives notice of any such claim shall relieve such indemnitor of
any liability to the indemnitee under this indemnity only if and to the extent
that such failure is prejudicial to its ability to defend such action, and the
omission so to deliver written notice to the indemnitor will not relieve it of
any liability that it may have to any indemnitee other than under this
indemnity. If an indemnitee settles a claim without the prior written consent of
the indemnitor, then the indemnitor shall be released from liability with
respect to such claim unless the indemnitor has unreasonably withheld such
consent.

     15.18 Section 1031 Exchange. Seller may consummate the sale of the Real
Property as part of a so-called like kind exchange (the "Exchange") pursuant to
ss. 1031 of the Internal Revenue Code of 1986, as amended (the "Code"), provided
that: (a) the Close of Escrow shall not be delayed or affected by reason of the
Exchange nor shall the consummation or accomplishment of the Exchange be a
condition precedent or condition subsequent to Seller's obligations under this
Agreement; (b) Seller shall effect the Exchange through an assignment of its
rights under this Agreement to a qualified intermediary; and (c) Buyer shall not
be required to take an assignment of the purchase agreement for the replacement
property or be required to acquire or hold title to the replacement property for
purposes of consummating the Exchange or to incur any cost or expense in
connection with the Exchange. Buyer shall not by this agreement or acquiescence
to the Exchange (1) have its rights under this Agreement affected or diminished
in any manner or (2) be responsible for compliance with or be deemed to have
warranted to Seller that the Exchange in fact complies with ss. 1031 of the
Code.

     15.19 Waiver of Jury Trial. To the extent permitted by applicable law, the
parties hereby waive any right to trial by jury in any legal proceeding arising
out of or relating to this Agreement or the transactions contemplated hereby.

     15.20 No Personal Liability. Notwithstanding anything stated to the
contrary herein, Seller's liability under this Agreement shall be limited to
Seller's interest in the Property and neither Seller, Seller's asset manager,
nor Seller's trustees, beneficiaries, officers, directors, members,
representatives, principals, partners, shareholders, constituent partners,
constituent principals, employees or agents shall have any personal liability
hereunder.

     15.21 Joint and Several Liability. If Buyer is composed of more than one
individual or entity, all obligations and liabilities of Buyer under this
Agreement shall be joint and several as to each of the individuals or entities
who compose Buyer.

     15.22 No Waiver. The failure of any party hereto to enforce at any time any
of the provisions of this Agreement shall in no way be construed as a waiver of
any of such provisions, or the right of any party thereafter to enforce each and
every such provision. No waiver of any breach of this Agreement shall be held to
be a waiver of any other or subsequent breach.

     15.23 Latent Defects. If the tenant under the Agilent Lease makes a written
claim of a "defect in design, construction, workmanship and materials" under
Section 3.4 of the Agilent Lease, then Seller shall, on behalf of Buyer,
actively pursue resolution of any such claim; provided, however, that Seller
shall not be required to take any such actions after the date which is one (1)
year from the Closing, and that Seller shall not be required to

                                      -25-

<PAGE>

incur in-house and/or third party costs and expenses in connection therewith in
excess of $100,000 (Seller's in-house professionals' time to have a value of
$150.00 per hour for such purposes).

                     [remainder of page intentionally blank]

                                      -26-


<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement under
seal as of the day and year first above written.


<TABLE>
<S>                                                   <C>
"BUYER"                                               "SELLER"


WELLS OPERATING PARTNERSHIP, L.P., a                  BPF TECH CENTRAL, LLC, a Delaware limited
Delaware limited partnership                          liability company
By:  Wells Real Estate Investment Trust, Inc., a
     Maryland corporation, its general partner        By:  Best Property Fund, L.P., a Delaware
                                                           limited partnership, its sole member

                                                           By:  BBS Investors II, a Delaware
                                                                general partnership, its general partner
     By: ____________________________________
         Name:                                                  By:  Schreiber Developments, LLC, a
         Title:                                                      California limited liability
                                                                     company, a general partner


                                                                     By: /s/ Charles J. Schreiber, Jr.
                                                                         -------------------------------
                                                                     Name: Charles J. Schreiber, Jr.
                                                                     Title:  Manager
</TABLE>



AGREED TO THIS 9/th/
DAY OF APRIL, 2002
AS TO PROVISIONS RELATING
TO ESCROW HOLDER:

CHICAGO TITLE INSURANCE COMPANY

By /s/ Joy Eaton
   ---------------------------------
 Its  AVP
    --------------------------------



<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement under
seal as of the day and year first above written.


<TABLE>
<S>                                                  <C>
"BUYER"                                              "SELLER"


WELLS OPERATING PARTNERSHIP, L.P., a                 BPF TECH CENTRAL, LLC, a Delaware
Delaware limited partnership                         limited liability company
By:  Wells Real Estate Investment Trust, Inc., a
     Maryland corporation, its general partner
                                                     By:  Best Property Fund, L.P., a Delaware
                                                          limited partnership, its sole member

                                                        By:  BBS Investors II, a Delaware
                                                             general partnership, its general partner
     By: /s/ Douglas P. Williams
         ------------------------------                      By:  Schreiber Developments, LLC, a
         Name: Douglas P. Williams                                California limited liability
         Title: Executive Vice President                          company, a general partner


                                                                  By:  ______________________________
                                                                  Name: Charles J. Schreiber, Jr.
                                                                  Title:  Manager
</TABLE>



AGREED TO THIS ____
DAY OF APRIL, 2002
AS TO PROVISIONS RELATING
TO ESCROW HOLDER:

CHICAGO TITLE INSURANCE COMPANY

By ________________________________

 Its ______________________________



<PAGE>

                         LIST OF EXHIBITS AND SCHEDULES


EXHIBIT A   --  Description of Real Property

EXHIBIT B   --  Description of Personal Property

EXHIBIT C   --  List of Service Contracts

EXHIBIT D   --  Form of Tenant Estoppel Certificate

EXHIBIT E   --  Form of Deed

EXHIBIT F   --  Form of Assignment of Leases, Service Contracts and Bill of Sale

EXHIBIT G   --  Form of FIRPTA Affidavit

EXHIBIT H   --  Form of Tenant Notice

EXHIBIT I   --  List of Construction and Architectural Contracts

EXHIBIT J   --  Form of Owner's Affidavit

EXHIBIT K   --  Form of Escrow Agreement

SCHEDULE 1  --  Description of New and Pending Lease Transactions

SCHEDULE 2  --  Commission Agreements

SCHEDULE 3  --  List of Warranties

SCHEDULE 4  --  List of Lawsuits

SCHEDULE 5  --  List of Leases