<PAGE>
                                                                    EXHIBIT 10.2


THE SECURITIES REPRESENTED BY THIS WARRANT HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY STATE SECURITIES LAWS.
SUCH SECURITIES MAY NOT BE TRANSFERRED WITHOUT SUCH REGISTRATION AND
QUALIFICATION UNLESS A PROPOSED TRANSFER OR SALE DOES NOT REQUIRE REGISTRATION
OR QUALIFICATION UNDER THE ACT OR APPLICABLE STATE LAW. ANY TRANSFER OF SUCH
SECURITIES IS ALSO SUBJECT TO THE CONDITIONS SPECIFIED IN THIS WARRANT. THIS
WARRANT PROVIDES FOR, AMONG OTHER THINGS, CERTAIN RESTRICTIONS UPON TRANSFER OF
THIS WARRANT AND THE SHARES OF COMMON STOCK OF THE COMPANY ISSUABLE UPON
EXERCISE HEREOF. BY ACCEPTING THIS WARRANT OR SUCH SHARES, THE HOLDER AGREES TO
BE BOUND BY ALL SUCH TRANSFER RESTRICTIONS IN THE WARRANT.



                                     WARRANT

             VOID AFTER 5:00 P.M., CHICAGO TIME, ON OCTOBER 3, 2005

                        WARRANT TO PURCHASE COMMON STOCK
                                       OF
                     SECURITY ASSOCIATES INTERNATIONAL, INC.



Date of Issuance:  October 3, 2001                          Certificate No. W-3


                  FOR VALUE RECEIVED, Security Associates International, Inc., a
Delaware corporation (the "COMPANY"), hereby grants to EGI-Fund (01) Investors,
L.L.C., a Delaware limited liability company, or its registered assigns
(collectively, the "REGISTERED HOLDER") the right to receive from the Company
Two Million Five Hundred Thousand (2,500,000) shares (the "AVAILABLE SHARES") of
Warrant Stock at a price per share of $2.50 (as adjusted from time to time
hereunder, the "EXERCISE PRICE"). This warrant is issued in connection with that
certain Stock Purchase Agreement dated as of October 3, 2001, by and among the
Company and the Registered Holder (such agreement, as amended through and after
the date hereof, the "PURCHASE AGREEMENT"). Certain capitalized terms used
herein are defined in Section 3 of this Warrant. The amount and kind of
securities purchasable pursuant to the rights granted under this Warrant and the
purchase price for such securities are subject to adjustment pursuant to the
provisions contained in this Warrant.



<PAGE>


                  This Warrant is subject to the following provisions:

1.   Exercise of Warrant.

     (a) Exercise Period. The Registered Holder may exercise, in whole or in
part, (but not as to a fractional share of Warrant Stock), the purchase rights
represented by this Warrant at any time and from time to time after the Date of
Issuance to and including 5:00 p.m., Chicago time, on October 3, 2005.

     (b) Exercise Procedure.

         (i) This Warrant shall be deemed to have been exercised when the
Company has received all of the following items (the "EXERCISE TIME"):

             (A) a completed Exercise Agreement, in the form set forth in
     Exhibit I hereto, executed by the Person exercising all or part of the
     purchase rights represented by this Warrant (the "PURCHASER");

             (B) this Warrant or, if this Warrant is not registered in the name
     of the Purchaser, an Assignment or Assignments executed by the Registered
     Holder in the form set forth in Exhibit II hereto evidencing the assignment
     of this Warrant by the Registered Holder; and

             (C) a certified or cashier's check payable to, or a wire transfer
     of immediately available funds to a United States account designated by the
     Company in an amount equal to the product of the Exercise Price multiplied
     by the number of shares of Warrant Stock being purchased upon such exercise
     (the "AGGREGATE EXERCISE PRICE").

         (ii) Certificates for shares of Warrant Stock purchased upon exercise
of this Warrant shall be delivered by the Company to the Purchaser within three
(3) business days after the Exercise Time. Unless this Warrant has expired or
all of the purchase rights represented hereby have been exercised, the Company
shall prepare a new Warrant, substantially identical hereto, representing the
purchase right formerly represented by this Warrant which have not expired or
been exercised and shall, within such three business day period, deliver such
new Warrant to the Person designated for delivery thereof in the Exercise
Agreement.

         (iii) The Warrant Stock issuable upon the exercise of this Warrant
shall be deemed to have been issued to the Purchaser at the Exercise Time, and
the Purchaser shall be deemed for all purposes to have become the record holder
of such Warrant Stock as of the Exercise Time.

         (iv) The issuance of certificates for shares of Warrant Stock upon
exercise of this Warrant shall be made without charge to the Registered Holder
or the Purchaser for any issuance or stamp tax in respect thereof or any other
cost incurred by the Company, the Purchaser or the Registered Holder in


                                       2
<PAGE>

connection with such exercise and the related issuance of shares of Warrant
Stock (and the Company shall pay such costs).

         (v) The Company shall not close its books against the transfer of this
Warrant or of any share of Warrant Stock issued or issuable upon the exercise of
this Warrant in any manner which interferes with the timely exercise of this
Warrant, or otherwise interfere with the timely exercise of this Warrant.

         (vi) Notwithstanding any other provision hereof, if an exercise of any
portion of this Warrant is to be made in connection with an underwritten public
offering of Common Stock, the exercise of any portion of this Warrant may, at
the election of the Registered Holder hereof, be conditioned upon the
consummation of such public offering, in which case such exercise shall not be
deemed to be effective until the consummation of such public offering and such
exercise may be limited to the number of shares of Warrant Stock included in
such public offering.

         (vii) The Company shall at all times reserve and keep available out of
its authorized but unissued shares of Common Stock, solely for the purpose of
purchase upon the exercise of this Warrant, such number of shares of Warrant
Stock as are issuable upon the exercise of this Warrant. All shares of Warrant
Stock which are so issuable shall, upon the payment of the Exercise Price and
issuance thereof, be duly and validly issued, fully paid and nonassessable. The
Company will pay such amounts and will take such other action as may be
necessary from time to time so that all shares of Warrant Stock which shall be
issued upon the exercise of the Warrants will, upon issuance and without cost to
the recipient, be free from all preemptive rights, taxes, liens and charges with
respect to the issue thereof. The Company shall take all such actions as may be
necessary to assure that all such shares of Warrant Stock may be so issued
without violation of any applicable law or governmental regulation.

     (c) Exercise Agreement. Upon any exercise of this Warrant, the Exercise
Agreement shall be substantially in the form set forth in Exhibit I hereto,
except that if the shares of Warrant Stock are not to be issued in the name of
the Registered Holder, the Exercise Agreement shall also state the name of the
Person to whom the certificates for the shares of Warrant Stock are to be
issued, and if the number of shares of Warrant Stock to be issued does not
include all the shares of Warrant Stock issuable hereunder, it shall also state
the name of the Person to whom a new Warrant for the unexercised portion of the
rights hereunder is to be delivered. Such Exercise Agreement shall be dated as
of the actual date of execution thereof.

     (d) Fractional Shares. If a fractional share of Warrant Stock would, but
for the provisions of Section 1(a), be issuable upon exercise of the rights
represented by this Warrant, the Company shall, within three (3) business days
after the date of the Exercise Time, deliver to the Purchaser a check payable to
the Purchaser in lieu of such fractional shares in an amount equal to the
difference between the Market Price of such



                                        3
<PAGE>

fractional share as of the date of the Exercise Time and the Exercise Price of
such fractional share.

2.   Adjustment of Number of Shares. The number of shares of Warrant Stock
obtainable upon exercise of this Warrant shall be subject to adjustment from
time to time as provided in this Section 2.

     (a) Subdivision or Combination of Shares. If the Company at any time
subdivides its outstanding shares of Common Stock, the Exercise Price in effect
immediately prior to such subdivision shall be proportionately decreased and the
number of shares of Warrant Stock obtainable upon exercise of this Warrant shall
be proportionately increased. If the Company at any time combines its
outstanding shares of Common Stock, the Exercise Price in effect immediately
prior to such combination shall be proportionately increased and the number of
shares of Warrant Stock obtainable upon exercise of this Warrant shall be
proportionately decreased.

     (b) Stock Dividends. If the Company at any time pays a dividend, or makes
any other distribution, to holders of Common Stock payable in shares of Common
Stock, the Exercise Price shall be decreased, and the number of shares of
Warrant Stock obtainable upon exercise of this Warrant shall be increased, by
multiplying the Exercise Price and dividing the number of obtainable shares of
Warrant Stock by the following fraction:

         (i) the total number of shares of Common Stock outstanding immediately
prior to such dividend or distribution,

         divided by

         (ii) the total number of shares of Common Stock outstanding immediately
after such dividend or distribution.

Such change shall be automatically effective as of the effectiveness of such
dividend or distribution.

     (c) Reclassification, Consolidation or Merger. If at any time, as a result
of:

         (i) a capital reorganization or reclassification (other than a
subdivision, combination or dividend provided for in Section 2(a) or Section
2(b)), or

         (ii) a merger or consolidation of the Company with another corporation
(whether or not the Company is the surviving corporation),

pursuant to which the Company's Common Stock shall be changed into or exchanged
for the same or a different number of shares of any class or classes of stock of
the Company or any other corporation, or other securities convertible into such
shares, then, as a part of




                                        4
<PAGE>

such reorganization, reclassification, merger or consolidation, appropriate
adjustments shall be made in the terms of this Warrant, so that:

                  (y) the Registered Holder shall thereafter be entitled to
                  receive, upon exercise of this Warrant, the kind and amount of
                  shares of stock, other securities, money and property which
                  such holder would have received at the time of such capital
                  reorganization, reclassification, merger, or consolidation, if
                  such holder had exercised this Warrant immediately prior to
                  such capital reorganization, reclassification, merger, or
                  consolidation, and

                  (z) this Warrant shall thereafter be adjusted on terms as
                  nearly equivalent as may be practicable to the adjustments
                  theretofore provided in this Section 2(c).

The provisions of this Section 2(c) shall similarly apply to successive capital
reorganizations, reclassifications, mergers, and consolidations.

     (d) Notice of Adjustments. Whenever the Exercise Price or the kind of
securities issuable upon the exercise of this Warrant shall be adjusted pursuant
to Section 2, the Company shall issue a certificate signed by (1) its President
or a Vice President and (2) by its Chief Financial Officer, Secretary or
Assistant Secretary, setting forth, in reasonable detail, the event requiring
the adjustment, the amount of the adjustment, the method by which such
adjustment was calculated (including a description of the basis on which the
Board of Directors of the Company made any determination hereunder), the
Exercise Price and the kind of securities issuable upon the exercise of this
Warrant after giving effect to such adjustment, and shall cause copies of such
certificate to be mailed (by first class mail postage prepaid) to each
Registered Holder promptly after each adjustment.

3.   Definitions. The following terms have meanings set forth below:

     (a) "COMMON STOCK" means the Company's common stock, par value $0.001 per
share.

     (b) "MARKET PRICE" of any security means the average of the closing prices
of such security's sales on all securities exchanges on which such security may
at the time be listed, including, without limitation, the American Stock
Exchange, or, if there have been no sales on any such exchange on any day, the
average of the highest bid and lowest asked prices on all such exchanges at the
end of such day, or, if on any day such security is not so listed, the average
of the representative bid and asked prices quoted in the NASDAQ System as of
4:00 P.M., New York time, or, if on any day such security is not quoted in the
NASDAQ System, the average of the highest bid and lowest asked prices on such
day in the domestic over-the-counter market as reported by the National
Quotation Bureau, Incorporated, or any similar successor organization, in each
such case averaged over a period of 21 days consisting of the day as of which
"MARKET PRICE" is




                                       5
<PAGE>

being determined and the 20 consecutive business days prior to
such day. If at any time such security is not listed on any securities exchange
or quoted in the NASDAQ System or the over-the-counter market, the "MARKET
PRICE" will be the fair value thereof as determined in good faith by the Board
of Directors of the Company.

     (c) "WARRANT STOCK" means the Company's Common Stock issuable upon exercise
of this Warrant; provided that if there is a change such that the securities
issuable upon exercise of this Warrant are issued by an entity other than the
Company or there is a change in the class of securities so issuable, then the
term "Warrant Stock" shall mean one share of the security issuable upon exercise
of this Warrant if such security is issuable in shares, or shall mean the
smallest unit in which such security is issuable if such security is not
issuable in shares.

     (d) "PERSON" means an individual, a partnership, a joint venture, a
corporation, a limited liability company, an insurance company, a bank, a trust,
an association, an unincorporated organization or a government or any department
or agency thereof.

4.   No Voting Rights; Board Representation. This Warrant shall not entitle the
Registered Holder to any voting rights or other rights as a stockholder of the
Company prior to the Exercise Time.

5.   Warrant Transferable; Restrictions. Subject to the transfer conditions and
restrictions referred to in this Section 5, the legend endorsed hereon and those
set forth in Section 8, this Warrant and the Warrant Stock issuable upon the
exercise of this Warrant and all rights hereunder are transferable, in whole or
in part, without charge to the Registered Holder, upon surrender of this Warrant
with a properly executed Assignment (in the form of Exhibit II hereto) at the
principal executive office of the Company. If all of the unexercised purchase
rights represented by this Warrant are not transferred pursuant to an
Assignment, the Company shall promptly execute and deliver to the Registered
Holder a new Warrant (bearing the original Date of Issuance) representing the
unexercised purchase rights not so transferred. Neither this Warrant nor the
Warrant Stock may be knowingly sold or otherwise disposed of by the Registered
Holder, directly or indirectly, to any Person whom the Company has theretofore
designated in writing to the Registered Holder to be a competitor of the
Company, which designations may be made from time to time by the Company's Board
of Directors in its reasonable, good faith discretion.

6.   Warrant Exchangeable for Different Denominations. This Warrant is
exchangeable in compliance with Section 8 upon the surrender hereof by the
Registered Holder at the principal executive office of the Company, for new
Warrants of like tenor representing in the aggregate the purchase rights
hereunder, and each such new Warrant shall represent such portion of such rights
as is designated by the Registered Holder at the time of such surrender. The
date the Company initially issues this Warrant shall be deemed to be the "DATE
OF ISSUANCE" hereof regardless of the number of times new certificates
representing the unexpired and unexercised rights formerly represented by this


                                       6
<PAGE>

Warrant shall be issued. All Warrants representing portions of the rights
hereunder are referred to herein as the "WARRANTS".

7.   Replacement. Upon receipt of evidence reasonably satisfactory to the
Company of the ownership and the loss, theft, destruction or mutilation of any
certificate evidencing this Warrant, and in the case of any such loss, theft or
destruction, upon receipt of an indemnity undertaking from the Registered Holder
of such certificate or such other Person satisfactory to the Company, or, in the
case of any such mutilation upon surrender of such certificate, the Company
shall execute and deliver in lieu of such certificate a new certificate of like
kind representing the same rights represented by such lost, stolen, destroyed or
mutilated certificate and dated the date of such lost, stolen, destroyed or
mutilated certificate.

8.   Transfer in Compliance with Applicable Securities Laws

     (a) This Warrant may not be assigned or transferred, except as provided
herein, and in accordance with and subject to the provisions of the Securities
Act of 1933, as amended, the rules and regulations promulgated thereunder (said
Act and such rules and regulations being hereinafter collectively referred to as
the "ACT") and applicable State securities laws. This Warrant and the shares of
Warrant Stock obtainable hereunder have not been registered under the Act or any
other applicable securities laws, and, accordingly, neither this Warrant nor any
of such Warrant Stock may be offered, sold, transferred, pledged, hypothecated
or otherwise disposed of unless registered pursuant to or in a transaction
exempt from registration under (evidenced by an opinion of inside or outside
counsel reasonably satisfactory to the Company or by such other means reasonably
acceptable to the Company) the Act and any other applicable state securities
laws.

     (b) Each certificate for Warrant Stock or for any other security issued or
issuable upon exercise of this Warrant shall contain the following legend on its
face unless, in the opinion of counsel reasonably satisfactory to Company, such
legend is not required:

         The shares represented by this certificate have not been registered
         under the Securities Act of 1933, as amended (the "ACT"), or any state
         securities laws. Such shares may not be transferred without such
         registration and qualification unless the proposed transfer or sale
         does not require registration or qualification under the Act or
         applicable state law. Any transfer of such securities is also subject
         to the conditions specified in the warrant to receive shares of Common
         Stock of Security Associates International, Inc. (the "COMPANY") dated
         as of October 3, 2001 (the "WARRANT"). The Warrant provides for, among
         other things, certain restrictions upon transfer of the Warrant and the
         shares of common stock of the Company issuable upon exercise thereof.
         By accepting such shares, the holder agrees to be bound by all such
         transfer restrictions. Copies of the form of such Warrant are on file
         with the Secretary of the Company at





                                       7
<PAGE>

         2101 S. Arlington Heights Road, Suite 150, Arlington Heights, IL 60005
         and will be furnished without charge by the Company to the holder of
         this certificate upon written request to the Secretary of the Company
         at such address.

9.   Notices. All notices, requests, waivers, releases, consents, and other
communications required or permitted by this Warrant (collectively, "NOTICES")
shall be in writing. Notices shall be deemed sufficiently given for all purposes
under this Warrant (i) when delivered in person, (ii) on the next business day
following the date when dispatched by telegram (upon written confirmation of
receipt), by electronic facsimile transmission (upon written confirmation of
receipt) or by a nationally recognized overnight courier service, or (iii) five
Business Days after being deposited in the United States certified or registered
mail, return receipt requested, first class postage prepaid. All Notices shall
be delivered (x) to the Company at its principal executive office or (y) to the
Registered Holder of this Warrant at such Registered Holder's address as it
appears in the records of the Company.

10.  Amendment and Waiver. Except as otherwise provided herein, the provisions
of the Warrants may be amended and the Company may take any action herein
prohibited, or omit to perform any act herein required to be performed by it,
only if the Company has obtained the written consent of the Registered Holders
of Warrants representing at least two-thirds (2/3) of the shares of Warrant
Stock obtainable upon exercise of the Warrants at the time of such approval.

11.  Description Headings; Governing Law. The descriptive headings of the
several Sections of this Warrant are inserted for convenience only and do not
constitute a part of this Warrant. The construction, validity and interpretation
of this Warrant shall be governed by the internal laws, without giving effect to
conflicts of law principles, of the State of Delaware.

                                    * * * * *



                                       8
<PAGE>


         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed
and attested by its duly authorized officers and to be dated as of the Date of
Issuance hereof.

                                         SECURITY ASSOCIATES INTERNATIONAL, INC.




                                         By: /s/ Raymond A. Gross
                                            ------------------------------------
                                         Name: Raymond A. Gross
                                              ----------------------------------
                                         Title: Chief Executive Officer
                                               ---------------------------------





                                       9
<PAGE>

                                    EXHIBIT I

                               EXERCISE AGREEMENT

To:________________________                                   Dated:____________

                  The undersigned, pursuant to the provisions set forth in the
attached Warrant (Certificate No. W-___), hereby subscribes for the purchase of
______________ shares of the Warrant Stock covered by such Warrant having an
Aggregate Exercise Price of $______________ and makes payment herewith in full
therefor by check or a wire transfer in immediately available funds in the
amount of the Aggregate Exercise Price ($___________).


Certificates for the shares of Warrant Stock subscribed for shall be issued to
the parties listed below:

         Name of Issuee             Address                   No. of Shares
         --------------             -------                   -------------




New Warrants for the rights not exercised hereunder shall be issued to the party
or parties listed below (with respect to such new Warrants, the "REGISTERED
HOLDER(S)"):


         Name of Issuee             Address                   No. of Shares
         --------------             -------                   -------------





                                              Signature
                                                       -------------------------

                                              Address
                                                     ---------------------------


<PAGE>


                                   EXHIBIT II

                                   ASSIGNMENT

         FOR VALUE RECEIVED, ___________________ hereby sells, assigns and
transfers all of the rights of the undersigned under the attached Warrant
(Certificate No. W-___) with respect to the number of shares of the Warrant
Stock covered thereby set forth below, unto, the following assignee (a
"REGISTERED HOLDER"):


         Name of Assignee           Address                   No. of Shares
         ----------------           -------                   -------------




Date                                          Signature
    --------------------------                         -------------------------

                                              Address
                                                     ---------------------------