<Page>
Exhibit 10.257
Allstate Life Insurance Company
Loan No. 122497
CLOSING CERTIFICATE
BEL AIR SQUARE LLC, a Maryland limited liability company ("Bel Air") hereby
makes the following representations and warranties to, and for the benefit of,
ALLSTATE LIFE INSURANCE COMPANY, an Illinois insurance corporation ("Lender"),
with the knowledge that Lender is relying thereon in making a $39,765,000 loan
(the "Loan") to INLAND BEL AIR SPE, L.L.C., a Delaware limited liability company
("Borrower") pursuant to the terms of that loan commitment dated June 23, 2004,
as amended (the "Commitment") between Bel Air and Lender. Initially capitalized
terms used but not defined herein have the same meanings given them in the
Indemnity Deed of Trust (the "Deed of Trust") securing the Payment Guaranty (the
"Guaranty") executed and delivered by Bel Air to secure the Loan.
(a) Bel Air has good and marketable title to the Property and has good
title to the other Collateral, free and clear of all liens or encumbrances other
than those to which Lender has specifically consented.
(b) No actions, suits, investigations, litigation, bankruptcy,
reorganization or other proceedings are pending at law or in equity or before
any federal, state, territorial, municipal or other government department,
commission, board, bureau, agency, courts or instrumentality, or to the best of
its knowledge, are threatened, against or affecting Bel Air or Borrower, its
sole member or general partner or the sole member or general partner of such
sole member or general partner, the operations of the Property or, to Bel Air's
actual knowledge, any tenant in the Improvements, (i) which would, as of the
date hereof, affect the validity or priority of the lien of the Deed of Trust,
(ii) which affect the ability of Bel Air or Borrower to perform its obligations
pursuant to and as contemplated by the terms and provisions of the Commitment,
or (iii) which could materially and adversely affect the operations or financial
condition of Bel Air or Borrower, its sole member or general partner or the sole
member or general partner of such sole member or general partner. None of Bel
Air or Borrower, its sole member or general partner or the sole member or
general partner of such sole member or general partner, has been adjudicated as
bankrupt, has never filed nor has had filed against it, any petition in
bankruptcy nor has otherwise taken advantage of any bankruptcy, insolvency or
other readjustment of debt laws.
(c) The execution, delivery and performance of the Commitment, the Note,
the Guaranty, the Deed of Trust, the Environmental Indemnity Agreement and the
other Loan Documents will not constitute a breach or default under any other
agreement to which Bel Air or Borrower is a party or may be bound or affected,
or a violation of any law or court order which may affect the Property, any part
thereof, any interest therein, or the use thereof.
(d) Neither Bel Air nor Borrower nor the sole member or general partner or
the sole member or general partner of such sole member or general partner of
either is in violation of or in default with respect to any term or provision of
any other loan commitments, mortgage, deed of trust, indenture, contract, or
instrument applicable to Bel Air, Borrower or the Property or by which it is
bound or with respect to any order, writ, injunction, decree or demand of any
court or any governmental agency or authority.
<Page>
(e) The rent roll attached as EXHIBIT A accurately reflects the leases and
income from the Property as of the date indicated thereon.
(f) Bel Air has not entered into any leases and there are no unrecorded
leases or other arrangements for occupancy of space within the Property other
than the leases reflected in the rent roll attached as EXHIBIT A.
(g) To Bel Air's actual knowledge, no condemnation of any portion of the
Property has commenced or, to the best of Bel Air's knowledge, is contemplated
by any governmental authority.
(h) All factual information set forth in the Commitment and its exhibits,
all financial statements, operating statements, leases and rent rolls previously
furnished by or on behalf of Bel Air or Borrower to Lender in connection with
the Loan and all other submissions referred to herein or required by the
Commitment are true, complete and correct in all material respects as of the
date indicated thereon, are not misleading in any material respect and do not
omit any information required to prevent such statements, loan submissions or
materials from being materially misleading under the circumstances.
(i) No material adverse change in the operations of the Property or in the
financial condition of Bel Air or Borrower has occurred since the date of
preparation of the most recent financial statements and operating statements
delivered to Lender.
(j) To Bel Air's actual knowledge, the Property is structurally sound and
the operation of the Property complies with all applicable zoning, environmental
protection or control codes and fire, electrical and building codes, rules and
regulations. To Bel Air's actual knowledge, there is no license, approval or
permit, necessary for either the lawful operation of the Property or the lawful
occupancy thereof, including, without limitation, utility, building, zoning,
subdivision control, land and water use, environmental protection and flood
hazard permits, which has not been obtained.
(k) To Bel Air's actual knowledge, Bel Air is not in default under any
lease; no tenant in the Improvements has committed an uncured monetary default
under its lease; all conditions precedent to any tenant's obligation to pay rent
have been satisfied and, to the best of Bel Air's knowledge, no tenant in the
Improvements has committed a nonmonetary default under its lease; no tenant
lease contains any option to purchase any interest in the Property.
(l) There are no unrecorded contracts to purchase the Property or any
interest therein.
(m) Except as otherwise set forth in the Phase I Environmental Site
Assessment of the Property prepared by PMT & Associates, Inc., dated May 28,
2004, and other than Hazardous Materials (as defined below) in quantities and of
types reasonably and customarily associated with general office use which have
been and are stored, used and disposed of in compliance with Hazardous Material
Laws (as defined below) and the presence of which do not require compliance with
any reporting requirements under any Hazardous Material Laws, no Hazardous
Materials have been installed, used, generated, manufactured, treated, handled,
refined, produced, processed, stored or disposed of, in, on or under the
Property, including without limitation, the surface and subsurface waters of the
Property, nor has any activity been
2
<Page>
undertaken on the Property which would cause; (i) the Property to become a
hazardous waste treatment, storage or disposal facility within the meaning of,
or otherwise bring the Property within, any Hazardous Material Laws; (ii) a
release or threatened release of Hazardous Material from the Property within the
meaning of, or otherwise bring the Property under, any Hazardous Material Laws;
or (iii) the discharge of Hazardous Material which would require a permit under
any Hazardous Material Laws. There are no conditions with respect to the
Property which would cause a violation or support a claim under any Hazardous
Material Laws. No underground storage tanks or underground deposits of Hazardous
Materials are or were located on the Property and subsequently removed or
filled. For purposes of this representation, "Hazardous Materials" means and
includes asbestos or any substance containing asbestos, polychlorinated
biphenyls, any explosives, radioactive materials, chemicals known or suspected
to cause cancer or reproductive toxicity, pollutants, effluents, contaminants,
emissions, infectious wastes, any petroleum or petroleum-derived waste or
product or related materials and any items defined as hazardous, special or
toxic materials, substances or waste under any Hazardous Material Laws, or any
material which shall be removed from the Property pursuant to any administrative
order or enforcement proceeding or in order to place the Property in a condition
that is suitable for ordinary use. "Hazardous Material Laws" means all federal,
state and local laws (whether under common law, statute or otherwise),
ordinances, rules, regulations and guidance documents now in force, as amended
from time to time, in any way relating to or regulating human health or safety,
industrial hygiene or environmental conditions, protection of the environment,
pollution or contamination of the air, soil, surface water or groundwater, and
includes, without limitation, the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, 42 U.S.C. Section 9601, et seq., the
Resource Conservation and Recovery Act, 42 U.S.C. Section 6901, et seq., the
Clean Water Act, 33 U.S.C. Section 1251, et seq., the Clean Air Act, 42 U.S.C.
Section 7401, et seq., the Occupational Safety and Health Act, 29 U.S.C. Section
651, et seq., the Hazardous Materials Transportation Act, 49 U.S.C. Section
1801, et seq., the Federal Water Pollution Control Act, 33 U.S.C. Section 1321,
et seq., and the Toxic Substances Control Act, 15 U.S.C. Section 2601, et seq.,
and the amendments, regulations, orders, decrees, permits, licenses or deed
restrictions now or hereafter promulgated thereunder.
(n) The Property consists of a separate tax lot or lots assessed
separately and apart from any other property owned by Bel Air or any other
owner.
(o) Based upon Bel Air's review of that certain ALTA Survey of the
Property prepared by Control. Point Associates, Inc., dated May 26, 2004, the
Property does not lie in a 100 year flood plain that has been identified by the
Secretary of Housing and Urban Development or any other governmental authority.
(p) The use of the Property by Bel Air and all tenants, subtenants,
licensees and other material users is in compliance with all use restrictions
contained in leases and restrictions affecting the Property.
Bel Air hereby agrees that these representations and warranties are also
made with the purpose of enabling the holders of the Deed of Trust, the Guaranty
and the Note, from time to time, to rely on the truth of the matters recited in
these representations and warranties as of the date they were made.
3
<Page>
This Closing Certificate shall be deemed to be a Related Agreement and a
Loan Document as defined in the Deed of Trust.
The above representations and warranties are all made as of the
Disbursement Date, as defined in the Note, and as of July 21, 2004.
BEL AIR SQAURE LLC,
a Maryland limited liability company
By: /s/ Steven P. Grimes
------------------------------
Name: Steven P. Grimes
---------------------------
Authorized Person
4
<Page>
EXHIBIT A
RENT ROLL