<PAGE>   1
                                                                   EXHIBIT 10.1




                                                                  EXECUTION COPY

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                      PROTECTION ONE ALARM MONITORING, INC.
                                       AND
               THE GUARANTORS NAMED ON THE SIGNATURE PAGES HERETO


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                                  $250,000,000
                           7 3/8% Senior Notes due 2005

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                               PURCHASE AGREEMENT


                              Dated August 12, 1998

                                 --------------

                            BEAR, STEARNS & CO. INC.
                              LEHMAN BROTHERS INC.
                        MORGAN STANLEY & CO. INCORPORATED
                              SALOMON BROTHERS INC












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<PAGE>   2











                      PROTECTION ONE ALARM MONITORING, INC.




                        $250,000,000 Principal Amount of


                           7 3/8% Senior Notes due 2005



                               PURCHASE AGREEMENT


                                                                 August 12, 1998

BEAR, STEARNS & CO. INC.
LEHMAN BROTHERS INC.
MORGAN STANLEY & CO. INCORPORATED
SALOMON BROTHERS INC
   c\o Bear, Stearns & Co. Inc.
   245 Park Avenue
   New York, New York 10167


Ladies and Gentlemen:

                  Protection One Alarm Monitoring, Inc. (the "Company") proposes
to issue and sell to Bear, Stearns & Co. Inc., Lehman Brothers Inc., Morgan
Stanley & Co. Incorporated and Salomon Brothers Inc (collectively, the "Initial
Purchasers") an aggregate of $250,000,000 in aggregate principal amount of 
7 3/8% Senior Notes due 2005 (the "Initial Notes"), subject to the terms and
conditions set forth herein. The Initial Notes will be issued pursuant to an
Indenture (the "Indenture"), to be dated the Closing Dated (as defined), among
the Company, the Guarantors (as defined) and The Bank of New York, as trustee
(the "Trustee"). The Notes (as defined) will be fully and unconditionally
guaranteed (the "Guarantees") as to payment of principal, interest, Liquidated
Damages (as defined) and premium, if any, on an unsecured senior basis, jointly
and severally, by each entity listed on Exhibit A hereto (collectively, the
"Guarantors"). Capitalized terms used herein and not otherwise defined shall
have the meanings assigned to such terms in the Indenture.

                  The net proceeds to the Company from the sale to the Initial
Purchasers of the Initial Notes (the "Proceeds") will be used by the Company:
(i) to repay a portion of the Senior Credit Facility (as defined) and (ii) for
general purposes and working capital.

                  1. ISSUANCE OF SECURITIES. The Company proposes, upon the
terms and subject to the conditions set forth herein, to issue and sell to the
Initial Purchasers an aggregate of $250,000,000 in aggregate principal amount of
Initial Notes. The Initial Notes and the Exchange Notes (as defined) issuable in
exchange therefor are collectively referred to herein as the "Notes."

                  Upon original issuance thereof, and until such time as the
same is no longer required under the applicable requirements of the Securities
Act of 1933, as amended (the "Act"), the Initial Notes (and all securities
issued in exchange therefor or in substitution thereof) shall bear the following
legend:



<PAGE>   3




                  "THIS SECURITY (OR ITS PREDECESSOR) HAS NOT BEEN REGISTERED
         UNDER THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE
         "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED, SOLD, PLEDGED
         OR OTHERWISE TRANSFERRED WITHIN THE UNITED STATES OR TO, OR FOR THE
         ACCOUNT OR BENEFIT OF, U.S. PERSONS, EXCEPT AS SET FORTH IN THE NEXT
         SENTENCE. BY ITS ACQUISITION HEREOF OR OF A BENEFICIAL INTEREST HEREIN,
         THE HOLDER: REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER"
         (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) (A "QIB"), (B) IT
         HAS ACQUIRED THIS SECURITY IN AN OFFSHORE TRANSACTION IN COMPLIANCE
         WITH REGULATION S UNDER THE SECURITIES ACT OR (C) IT IS AN
         INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A) (1),
         (2), (3) OR (7) OR REGULATION D UNDER THE SECURITIES ACT) (AN "IAI"),
         AGREES THAT IT WILL NOT RESELL OR OTHERWISE TRANSFER THIS SECURITY
         EXCEPT (A) TO THE COMPANY OR ANY OF ITS SUBSIDIARIES, (B) TO A PERSON
         WHOM THE SELLER REASONABLY BELIEVES IS A QIB PURCHASING FOR ITS OWN
         ACCOUNT OR FOR THE ACCOUNT OF A QIB IN A TRANSACTION MEETING THE
         REQUIREMENTS OF RULE 144A, (C) IN AN OFFSHORE TRANSACTION MEETING THE
         REQUIREMENTS OF RULE 903 OR 904 OF THE SECURITIES ACT, (D) IN A
         TRANSACTION MEETING THE REQUIREMENTS OF RULE 144 UNDER THE SECURITIES
         ACT, (E) TO AN IAI THAT, PRIOR TO SUCH TRANSFER, FURNISHES THE TRUSTEE
         A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
         RELATING TO THE TRANSFER OF THIS SECURITY (THE FORM OF WHICH CAN BE
         OBTAINED FROM THE TRUSTEE) AND, IF SUCH TRANSFER IS IN RESPECT OF AN
         AGGREGATE PRINCIPAL AMOUNT OF SECURITIES LESS THAN $250,000, AN OPINION
         OF COUNSEL ACCEPTABLE TO THE COMPANY THAT SUCH TRANSFER IS IN
         COMPLIANCE WITH THE SECURITIES ACT, (F) IN ACCORDANCE WITH ANOTHER
         EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT (AND
         BASED UPON AN OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY) OR (G)
         PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT AND, IN EACH CASE, IN
         ACCORDANCE WITH THE APPLICABLE SECURITIES LAWS OF ANY STATE OF THE
         UNITED STATES OR ANY OTHER APPLICABLE JURISDICTION AND AGREES THAT IT
         WILL DELIVER TO EACH PERSON TO WHOM THIS NOTE OR AN INTEREST HEREIN IS
         TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND."

                  "AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION" AND "UNITED
         STATES" HAVE THE MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION S
         UNDER THE SECURITIES ACT. THE INDENTURE CONTAINS A PROVISION REQUIRING
         THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF THIS NOTE IN
         VIOLATION OF THE FOREGOING."

                  2. OFFERING. The Initial Notes will be offered and sold to the
Initial Purchasers pursuant to an exemption from the registration requirements
under the Act. The Company has prepared a preliminary offering memorandum, dated
August 3, 1998 (the "Preliminary Offering Memorandum"), and 

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<PAGE>   4




a final offering memorandum, dated August 12, 1998 (the "Offering Memorandum"),
relating to the Company, the Guarantors and their respective subsidiaries and
the Initial Notes.

                  The Initial Purchasers have advised the Company that the
Initial Purchasers will make offers (the "Exempt Resales") of the Initial Notes
on the terms set forth in the Offering Memorandum, as amended or supplemented,
solely to persons whom the Initial Purchasers reasonably believe to be
"qualified institutional buyers," as defined in Rule 144A under the Act
("QIBs"). The QIBs are referred to herein as the "Eligible Purchasers." The
Initial Purchasers will offer the Initial Notes to such Eligible Purchasers
initially at a price equal to 99.778% of the principal amount thereof. Such
price may be changed at any time without notice.

                  Holders (including subsequent transferees) of Initial Notes
will have the registration rights set forth in the registration rights agreement
relating thereto (the "Registration Rights Agreement"), to be dated the Closing
Date, for so long as such Initial Notes constitute "Transfer Restricted
Securities" (as defined in the Registration Rights Agreement"). Pursuant to the
Registration Rights Agreement, the Company and the Guarantors will agree to file
with the Securities and Exchange Commission (the "Commission"), under
circumstances set forth therein, (i) a registration statement under the Act (the
"Exchange Offer Registration Statement"), relating to the 73/8% Exchange Senior
Notes due 2005 (the "Exchange Notes") to be offered in exchange for the Initial
Notes (the "Exchange Offer") or (ii) a shelf registration statement pursuant to
Rule 415 under the Act (each of the "Shelf Registration Statement" and the
Exchange Offer Registration Statement, being referred to as a "Registration
Statements"), relating to the resale by certain holders of the Initial Notes,
and to use their best efforts to cause such Registration Statements to be
declared effective and to consummate the Exchange Offer. This Agreement, the
Notes, the Guarantees, the Indenture and the Registration Rights Agreement are
hereinafter referred to collectively as the "Operative Documents."

                  3. DELIVERY AND PAYMENT. On the basis of the representations,
warranties and covenants contained in this Agreement, and subject to its terms
and conditions, the Company agrees to issue and sell to the Initial Purchasers,
and each Initial Purchaser agrees, severally and not jointly, to purchase from
the Company, the principal amount of Initial Notes set forth opposite its name
on Schedule I hereto. The purchase price for the Initial Notes will be $999.778
per $1,000 principal amount of Initial Note.

                  Delivery of the Initial Notes shall be made, against payment
of the purchase therefor, at the offices of Weil, Gotshal & Manges LLP, 100
Crescent Court, Suite 1300, Dallas, Texas 75201-6950 or such other location as
may be mutually acceptable. Such delivery and payment shall be made at 9:00
a.m., Dallas time or 10:00 a.m. New York City time on August 17, 1998 or at such
other time as shall be agreed upon by the Initial Purchasers and the Company.
The time and date of such delivery and payment are herein called the "Closing
Date."

                  On the Closing date, one or more Initial Notes in definitive
form, registered in the name of Cede & Co., as nominee of The Depository Trust
Company ("DTC"), having an aggregate amount corresponding to the aggregate
amount of the Initial Notes sold pursuant to the Exempt Resales to Eligible
Purchasers (the "Global Notes") shall be delivered by the Company to the Initial
Purchasers (or as the Initial Purchasers may direct), against payment by the
Initial Purchasers of the purchase price therefor, by wire transfer of same day
funds, to an account designated by the Company; provided, however, that the
Company shall give at least two business days' prior written notice to the
Initial Purchasers of the information required to effect such wire transfer. The
Global Notes shall be made available to the Initial 



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<PAGE>   5


Purchasers for inspection not later than 10:00 a.m., New York City time, on the
business day immediately preceding the Closing Date.

                  4. CERTAIN COVENANTS OF THE COMPANY AND THE GUARANTORS. Each
of the Company and the Guarantors, jointly and severally, covenant and agree:

                  (a) To advise the Initial Purchasers promptly and, if
         requested by the Initial Purchasers, confirm such advice in writing,
         (i) of the issuance by any state securities commission of any stop
         order suspending the qualification or exemption from qualification of
         any Notes for offering or sale in any jurisdiction, or the initiation
         of any proceeding for such purpose by any state securities commission
         or other regulatory authority and (ii) of the happening of any event
         known to the Company or the Guarantors on or before the Closing Date
         which in the judgement of the Company and the Guarantors would require
         the making of any change in the Offering Memorandum or in the
         information incorporated by reference therein so that as therefore
         delivered to purchasers the Offering Memorandum will not include any
         untrue statement of material fact or omit to state a material fact
         necessary in order to make the statements therein, in the light of the
         circumstances under which they are made, not misleading. The Company
         and the Guarantors shall use their respective reasonable best efforts
         to prevent the issuance of any stop order or order suspending the
         qualification or exemption of any Notes under any state securities or
         Blue Sky laws and, if at any time any state securities commission or
         other regulatory authority shall issue an order suspending the
         qualification or exemption of any Notes or the Guarantees under any
         state securities or Blue Sky laws, the Company and the Guarantors shall
         use their respective reasonable best efforts to obtain the withdrawal
         or lifting of such order at the earliest possible time, and on request
         to prepare and furnish to the Initial Purchasers and to dealers and
         other persons designated by the Initial Purchasers such amendments or
         supplements (including appropriate filings under the Exchange Act) to
         the Offering Memorandum as may be necessary to any such change,
         provided that the Company shall be so obligated subsequent to the time
         of purchase only so long as the Company is notified of unsold
         allotments (failure by the Initial Purchasers to so notify the Company
         cancels the Company's obligation under this Section 4(a)).

                  (b) To as soon as practicable, make generally available to its
         security holders an earnings statement (as contemplated by Rule 158
         under the Act) covering a period of twelve months after the effective
         date (as the term "effective date" is defined in Rule 158) of the
         Offering Memorandum.

                  (c) To furnish such proper information as may be required and
         otherwise to cooperate in qualifying the Initial Notes for sale under
         the laws of such jurisdictions as the Initial Purchasers may designate
         and in determining their eligibility for investment under the laws of
         such jurisdiction; provided that the Company and the Guarantors shall
         not hereby be required to qualify as a foreign corporation or to file a
         general consent to service of process in any jurisdiction.

                  (d) To deliver to the Initial Purchasers without charge as
         soon as practicable after the execution and delivery of this Agreement
         and thereafter from time to time to furnish to the Initial Purchasers,
         without charge, as many copies of the Offering Memorandum in final form
         and any documents incorporated by reference therein at or after the
         date thereof, as the Initial Purchasers may reasonably request in
         connection with Exempt Resales.

                  (e) To pay the reasonable fees and expenses of counsel for the
         Initial Purchasers, and to reimburse the Initial Purchasers for their
         reasonable out-of-pocket expenses incurred in 


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<PAGE>   6


         contemplation of the performance of this Agreement, in the event that
         the Initial Notes are not delivered to and taken up and paid for by the
         Initial Purchasers hereunder for any reason whatsoever except the
         failure or refusal of any Initial Purchaser to take up and pay for the
         Initial Notes for some reason not permitted by the terms of this
         Agreement, the Initial Purchasers agreeing to pay the fees and expenses
         of counsel for the Initial Purchasers in any other event. To pay all
         expenses, fees and taxes (other than transfer taxes and fees and
         disbursements of counsel for the Initial Purchasers, except as set
         forth under the preceding sentence or (iv) below) in connection with
         (i) the preparation of the Preliminary Offering Memorandum and the
         Offering Memorandum, any documents incorporated by reference therein at
         or after the date thereof and any amendments or supplements thereto,
         and the printing and furnishing of copies of each thereof to the
         Initial Purchasers and to dealers, (ii) the issue, sale and delivery of
         the Initial Notes, (iii) the printing and reproduction of this
         Agreement and the opinions and letters referred to in Section
         5(e),(f),(g) and (i) hereof, (iv) the qualification of the Initial
         Notes for sale and determination of their eligibility for investment
         under state laws as aforesaid, including the legal fees (not to exceed
         $3,000) and all filing fees and disbursements of counsel for the
         Initial Purchasers and all other filing fees, and the printing and
         furnishing of copies of the "Blue Sky Memorandum" and the "Legal
         Investment Survey" to the Initial Purchasers and to dealers, (v) the
         rating of the Initial Notes by national rating agencies and (vi) the
         performance of the other obligations of the Company and the Guarantors
         hereunder.

                  (f) To use the proceeds from the sale of the Initial Notes in
         the manner described in the Offering Memorandum under the caption "Use
         of Proceeds."

                  (g) Not to sell, offer for sale or solicit offers to buy or
         otherwise negotiate in respect of any security (as defined in the Act)
         that would be integrated with the sale of the Initial Notes in a manner
         that would require the registration under the Act of the sale to the
         Initial Purchasers or the Eligible Purchasers of the Initial Notes or
         to take any other action that would result in the Exempt Resales not
         being exempt from registration under the Act.

                  (h) For so long as any of the Notes remain outstanding and
         during any period in which the Company and the Guarantors are not
         subject to Section 13 or 15(d) of the Securities Exchange Act of 1934,
         as amended (the "Exchange Act"), to make available to any holder or
         beneficial owner of Initial Notes in connection with any sale thereof
         and any prospective purchaser of such Notes from such holder or
         beneficial owner, upon request of such holder, the information required
         by Rule 144A(d) (4) under the Act.

                  (i) To furnish to the Initial Purchasers, at or before the
         time of filing with the Commission subsequent to the date hereof and up
         to and including the Closing Date, a copy of any document proposed to
         be filed by the Company or any Guarantor pursuant to Section 13(a),
         13(d), 14 or 15(d) of the Exchange Act.

                  (j) Not to take, directly or indirectly, any action designed
         to, or that might reasonably be expected to, cause or result in
         stabilization or manipulation of the price of any security of the
         Company or any of the Guarantors to facilitate the sale or resale of
         the Notes. Except as permitted by the Act, none of the Company or the
         Guarantors will distribute any (i) preliminary offering memorandum,
         including, without limitation, the Preliminary Offering Memorandum,
         (ii) offering memorandum, including, without limitation, the Offering
         Memorandum, or (iii) other offering material in connection with the
         offering and sale of the Notes.



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<PAGE>   7


                  5. CONDITIONS OF INITIAL PURCHASERS' OBLIGATIONS. The several
obligations of the Initial Purchasers to purchase and pay for the Initial Notes,
as provided herein, shall be subject to the following conditions:

                  (a) The Offering Memorandum shall not contain an untrue
         statement of a material fact or omit to state a material fact required
         to be stated therein or necessary to make the statements therein not
         misleading, and the Offering Memorandum as of its date and the Closing
         Date shall not contain an untrue statement of a material fact or omit
         to state a material fact required to be stated therein or necessary to
         make the statements therein, in the light of the circumstances under
         which they were made, not misleading, other than any statements
         contained in, or any matter omitted from, the Offering Memorandum in
         reliance upon, and in conformity with, information furnished in writing
         by or on behalf of any Initial Purchaser to the Company expressly for
         use with reference to such Initial Purchaser. Each of the Company and
         the Guarantors shall have performed all of its obligations under this
         Agreement which are to be performed by the terms hereof at or before
         the Closing Date.

                  (b) All orders, approvals or consents of state or federal
         regulatory commissions necessary to permit the issue, sale and delivery
         of the Initial Notes and the Guarantees shall have been issued; at the
         Closing Date such orders shall be in full force and effect; and prior
         to such time of purchase no stop order with respect to the Initial
         Notes or the Guarantees shall have been issued by the Commission and at
         the Closing Date no proceeding thereof shall be pending or threatened.

                  (c) Since the dates as of which information is given in the
         Offering Memorandum and prior to the Closing Date, there shall not have
         taken place a material adverse change in the condition of the Company
         or the Guarantors, financial or otherwise (other than as referred to in
         or contemplated by the Offering Memorandum), which in the reasonable
         judgment of the Initial Purchasers, is sufficiently material and
         adverse so as to render it impracticable or inadvisable to offer or
         deliver the Initial Notes on the terms and in the manner contemplated
         by the Offering Memorandum.

                  (d) The Initial Purchasers shall have received signed
         certificates of two executive officers, dated the Closing Date, signed
         on behalf of the Company and the Guarantors, confirming, as of the
         Closing Date, the matters set forth in paragraphs (a) and (c) of this
         Section 5.

                  (e) The Initial Purchasers shall have received on the Closing
         Date an opinion, dated the Closing Date, in form and substance
         reasonably satisfactory to the Initial Purchasers and counsel for the
         Initial Purchasers, of Weil, Gotshal & Manges LLP, counsel for the
         Company and the Guarantors, to the effect set forth in Exhibit B
         hereto.

                  (f) The Initial Purchasers shall have received on the Closing
         Date an opinion, dated on the Closing Date, in form and substances
         reasonably satisfactory to the Initial Purchasers and counsel for the
         Initial Purchasers, of Renee T. Kingsley, General Counsel for the
         Company and the Guarantors, to the effect set forth in Exhibit C
         hereto.

                  (g) The Initial Purchasers shall have received on the Closing
         Date an opinion, dated on the Closing Date, in form and substances
         reasonably satisfactory to the Initial Purchasers and counsel for the
         Initial Purchasers, of Rick Terrill, General Counsel for Westar
         Securities, Inc., a Kansas corporation and WestSec, Inc., a Kansas
         corporation (collectively, the "Other Guarantors"), to the effect set
         forth in Exhibit D hereto.


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<PAGE>   8


                  (h) The Initial Purchasers shall have received an opinion,
         dated the Closing Date, in form and substance reasonably satisfactory
         to the Initial Purchasers, of Latham & Watkins, counsel for the Initial
         Purchasers, covering such matters as are customarily covered in such
         opinions.

                  (i) At the time this Agreement is executed and at the Closing
         Date, the Initial Purchasers shall have received from Arthur Andersen
         LLP, independent public accountants, dated as of the date of this
         Agreement and as of the Closing Date, customary comfort letters
         addressed to the Initial Purchasers and in form and substance
         satisfactory to the Initial Purchasers and counsel for the Initial
         Purchasers with respect to the financial statements and certain
         financial information of the Company, the Guarantors and their
         respective subsidiaries contained or incorporated by reference in the
         Offering Memorandum.

                  (j) Latham & Watkins shall have been furnished with such
         documents, in addition to those set forth above, as they may reasonably
         require for the purpose of enabling them to review or pass upon the
         matters referred to in this Section 5 and in order to evidence the
         accuracy, completeness or satisfaction in all material respects of any
         of the representations, warranties or conditions herein contained.

                  (k) The Company, the Guarantors and the Trustee shall have
         entered into the Indenture and the Initial Purchasers shall have
         received counterparts, conformed as executed, thereof.

                  (l) The Company and the Guarantors shall have entered into the
         Registration Rights Agreement and the Initial Purchasers shall have
         received counterparts, conformed as executed, thereof.

                  (m) Subsequent to the date of this Agreement and prior to the
         Closing Date: (i) no downgrading shall have occurred in the rating
         accorded to any class of securities of the Company by any "nationally
         recognized securities rating organization," as defined by the
         Commission for purposes of its Rule 436(g)(2); (ii) no such rating
         organization shall have announced publicly subsequent to the date of
         this Agreement that it has placed, or informed the Company or the
         Initial Purchasers that it intends to place, any class of securities on
         what is commonly referred to as a "watchlist" for possible downgrading,
         in a manner or to an extent indicating a materially greater likelihood
         of a downgrading as described in clause (i) above occurring than was
         the case as of the date hereof.

                  (n) The Company and the Guarantors shall have given notice to
         each of trustees under the Discount Notes Indenture and the Convertible
         Notes Indenture that the Company is hereby designating the Notes to be
         Senior Indebtedness (as defined in each such indenture) and that the
         Guarantors are hereby designating their Guarantees to be senior
         Guarantees. The Company and the Guarantors shall have complied with all
         notice requirements under each such indenture.

                  6.       TERMINATION OF AGREEMENT.

                  (a) The obligations of the several Initial Purchasers
         hereunder shall be subject to termination in the Initial Purchasers'
         absolute discretion, if, at any time prior to the time of purchase,
         trading in securities on the New York Stock Exchange shall have been
         suspended (other than a temporary suspension to provide for an orderly
         market) or minimum prices shall have been 


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<PAGE>   9


         established on the New York Stock Exchange, or if a banking moratorium
         shall have been declared either by the United States or New York State
         authorities, or if the United States shall have declared war in
         accordance with its constitutional processes or there shall have
         occurred any outbreak or material escalation of hostilities or other
         national or international calamity or crisis of such magnitude in its
         effect on the financial markets of the United States as, in the
         reasonable judgment of the Initial Purchasers, to make it impracticable
         to market the Initial Notes.

                  (b) If the Initial Purchasers elect to terminate this
         Agreement as provided in this Section 6, the Company and each other
         Initial Purchasers shall be notified promptly in writing or by
         telephone, confirmed in writing.

                  (c) If the sale to the Initial Purchasers of the Initial
         Notes, as herein contemplated, is not carried out by the Initial
         Purchasers for any reason permitted hereunder or if such sale is not
         carried out because the Company or the Guarantors shall be unable to
         comply with any of the terms hereof, the Company and the Guarantors
         shall not be under any obligation or liability under this Agreement
         (except to the extent provided in Sections 4(e), 9(a) and 10 hereof),
         and the Initial Purchasers shall be under no obligation or liability to
         the Company (except to the extent provided in Sections 9(b) and 10
         hereof) or to one another under this Agreement.

                  7. WARRANTIES AND REPRESENTATIONS OF THE COMPANY AND THE
GUARANTORS. Each of the Company and the Guarantors, severally and jointly,
represent and warrant to, and agree with the Initial Purchasers that:

                  (a) (i) Each document, if any, filed or to be filed pursuant
         to the Exchange Act and incorporated by reference in the Offering
         Memorandum complied or will comply when so filed in all material
         respects with the Exchange Act and the applicable rules and regulations
         of the Commission thereunder and (ii) the Offering Memorandum, in the
         form used by the Initial Purchasers to confirm sales and on the Closing
         Date, will not contain any untrue statement of a material fact or omit
         to state a material fact necessary to make the statements therein, in
         the light of the circumstances under which they were made, not
         misleading, except that the representations and warranties set forth in
         this paragraph do not apply to statements or omissions in the Offering
         Memorandum based upon information furnished to the Company in writing
         by or on behalf of any Initial Purchaser expressly for use therein.

                  (b) Each subsidiary of Protection One, Inc. (other than the
         Company) that has executed the Senior Credit Facility, the Discount
         Notes Indenture (as defined in the Offering Memorandum) or the
         Convertible Notes Indenture (as defined in the Offering Memorandum) in
         the capacity as guarantor is listed on Exhibit A hereto.

                  (c) Neither the Company nor, to the Company's knowledge, any
         affiliate (as defined in Rule 501(b) of Regulation D under the Act, an
         "Affiliate") of the Company has directly, or through any agent, (i)
         sold, offered for sale, solicited offers to buy or otherwise negotiated
         in respect of, any security (as defined in the Act) which is or will be
         integrated with the sale of the Initial Notes in a manner that would
         require the registration under the Act of the Initial Notes or (ii)
         engaged in any form of general solicitation or general advertising in
         connection with the offering of the Notes (as those terms are used in
         Regulation D under the Act), or in any manner involving a public
         offering within the meaning of Section 4(2) of the Act.



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<PAGE>   10



                  (d) The Initial Notes satisfy the requirements set forth in
         Rule 144A(d)(3) under the Act.

                  (e) No form of general solicitation or general advertising
         (within the meaning of Regulation D under the Act) was used by the
         Company, the Guarantors or any of their respective representatives
         (other than the Initial Purchasers, as to whom the Company and the
         Guarantors make no representation) in connection with the offer and
         sale of the Initial Notes contemplated hereby, including, but not
         limited to, articles, notices or other communications, published in any
         newspaper, magazine, or similar medium or broadcast over television or
         radio, or any seminar or meeting whose attendees have been invited by
         any general solicitation or general advertising. No securities of the
         same class as the Initial Notes have been issued and sold by the
         Company within the six-month period immediately prior to the date
         hereof.

                  (f) Assuming the accuracy of the Initial Purchasers'
         representations and warranties and compliance by the Initial Purchasers
         with their agreements contained in Section 8 hereof, it is not
         necessary in connection with the offer, sale and delivery of the
         Initial Notes to the Initial Purchasers and to Eligible Purchasers in
         the manner contemplated by this Agreement and the Offering Memorandum
         to register the Initial Notes under the Act or to qualify the Indenture
         under the TIA.

                  Each of the Company and the Guarantors understand that the
Initial Purchasers and, for purposes of the opinions to be delivered to the
Initial Purchasers pursuant to Section 8 hereof, counsels to the Company and
Guarantors, and counsel to the Initial Purchasers will rely upon the accuracy
and truth of the foregoing representations and hereby consents to such reliance.

                  8. WARRANTIES AND REPRESENTATIONS OF THE INITIAL PURCHASERS.
Each of the Initial Purchasers, severally and not jointly, represents, warrants
and covenants to the Company and agrees that:

                  (a) Such Initial Purchaser is a QIB, with such knowledge and
         experience in financial and business matters as are necessary in order
         to evaluate the merits and risks of an investment in the Initial Notes.

                  (b) Such Initial Purchaser is not acquiring the Initial Notes
         with a view to any distribution thereof that would violate the Act or
         the securities laws of any state of the United States or any other
         applicable jurisdiction.

                  (c) No form of general solicitation or general advertising
         (within the meaning of Regulation D under the Act) has been or will be
         used by such Initial Purchaser or any of its representatives in
         connection with the offer and sale of any of the Initial Notes,
         including, but not limited to, articles, notices or other
         communications published in any newspaper, magazine, or similar medium
         or broadcast over television or radio, or any seminar or meeting whose
         attendees have been invited by any general solicitation or general
         advertising.

                  (d) Each of the Initial Purchasers agrees that, in connection
         with the Exempt Resales, it will solicit offers to buy the Initial
         Notes only from, and will offer to sell the Initial Notes only to,
         Eligible Purchasers. Each of the Initial Purchasers further (A) agrees
         that it will offer to sell the Initial Notes only to, and will solicit
         offers to buy the Initial Notes only from Eligible Purchasers, (B)
         acknowledges and agrees that, in the case of such Eligible Purchasers,
         such Initial Notes will 


                                       9

<PAGE>   11


         not have been registered under the Act and may be resold, pledged or
         otherwise transferred by such Eligible Purchasers only (x)(I) to a
         person whom the seller reasonably believes is a QIB purchasing for its
         own account or for the account of a QIB in a transaction meeting the
         requirements of Rule 144A, (II) in an offshore transaction (as defined
         in Rule 902 under the Act) meeting the requirements of Rule 904 under
         the Act, (III) in a transaction meeting the requirements of Rule 144
         under the Act, (IV) to an Accredited Investor that, prior to such
         transfer, furnishes the Trustee a signed letter containing certain
         representations and agreements relating to the registration of transfer
         of such Initial Notes and, if such transfer is in respect an aggregate
         principal amount of Initial Notes less than $250,000, an opinion of
         counsel acceptable to the Company that such transfer is in compliance
         with the Act or (V) in accordance with another exemption from the
         registration requirements of the Act (and based upon an opinion of
         counsel if the Company so requests), (y) to the Company, (z) pursuant
         to an effective registration statement under the Act and, in each case,
         in accordance with any applicable securities laws of any state of the
         United States or any other applicable jurisdiction and (C) acknowledges
         that it will, and each subsequent holder is required to, notify any
         purchaser of the security evidenced thereby of the resale restrictions
         set forth in (B) above.

                  (e) Each Initial Purchaser warrants and represents that the
         information furnished in writing by or on behalf of such Initial
         Purchaser to the Company expressly for use with reference to such
         Initial Purchaser in the Offering Memorandum at the time it was
         prepared, will not contain an untrue statement of a material fact and
         will not omit to state a material fact in connection with such
         information required to be stated in the Offering Memorandum or
         necessary to make such information not misleading. Each Initial
         Purchaser, in addition to other information furnished by such Initial
         Purchaser in writing expressly for use with reference to such Initial
         Purchaser in the Offering Memorandum, hereby furnishes to the Company
         in writing expressly for use with reference to such Initial Purchaser
         the statements with respect to the terms of the offering of the Initial
         Notes by the Initial Purchasers set forth on the cover page of the
         Offering Memorandum and under "Plan of Distribution" therein.

                  The Initial Purchasers acknowledge that the Company and, for
purposes of the opinions to be delivered to the Initial Purchasers pursuant to
Section 8 hereof, counsel for the Company and the Guarantors and counsel for the
Initial Purchasers will rely upon the accuracy and truth of the foregoing
representations and hereby consents to such reliance.

                  9.       INDEMNIFICATION.

                  (a) The Company and the Guarantors, jointly and severally,
         agree to indemnify and hold harmless each Initial Purchaser, and any
         person who controls any Initial Purchaser within the meaning of Section
         15 of the Act or Section 20 of the Exchange Act, from and against any
         loss, expense, liability or claim which arises out of or is based upon
         any alleged untrue statement of a material fact in the Preliminary
         Offering Memorandum or the Offering Memorandum, or in any supplement
         thereto or amendment thereof, or arises out of or is based upon any
         alleged omission to state therein a material fact required to be stated
         therein or necessary to make the statements made therein in light of
         the circumstances under which they were made not misleading. The
         foregoing shall not cover any such loss, expense, liability or claim,
         however, which arises out of or is based upon any alleged untrue
         statement of a material fact contained in, and in conformity with
         information furnished in writing by or on behalf of any Initial
         Purchaser to the Company expressly for use with reference to the
         Initial Purchaser in, any such documents or arises out of or is based
         upon any alleged omission to state a material fact in connection with
         such information required to


                                       10



<PAGE>   12


         be stated in any such documents or necessary to make such information
         not misleading. If any action is brought against an Initial Purchaser
         or controlling person in respect of which indemnity may be sought
         against the Company and the Guarantors pursuant to this paragraph, such
         Initial Purchaser shall promptly notify the Company in writing or by
         telephone, confirmed in writing, of the institution of such action, and
         the Company and the Guarantors shall assume the defense of such action,
         including the employment of counsel and payment of expenses; provided,
         however, that the failure so to notify the Company will not relieve it
         from any liability that it may have to such Initial Purchaser under
         this Section 9(a) unless, and only to the extent that, such failure
         results in the forfeiture of substantive rights or defenses by the
         Company or the Guarantors. Such Initial Purchaser or controlling person
         shall have the right to employ its or their own counsel in any such
         case, but the fees and expenses of such counsel shall be at the expense
         of such Initial Purchaser or such controlling person unless the
         employment of such counsel shall have been authorized in writing by the
         Company in connection with the defense of such action or the Company
         and the Guarantors shall not have employed counsel to have charge of
         the defense of such action or such indemnified party or parties shall
         have reasonably concluded that there may be defenses available to it or
         them which are different from or additional to those available to the
         Company or the Guarantors (in which case the Company and the Guarantors
         shall not have the right to direct the defense of such action on behalf
         of the indemnified party or parties), in any of which events such fees
         and expenses of one counsel for all indemnified parties selected by
         such Initial Purchaser shall be borne by the Company and the
         Guarantors. Anything in this paragraph to the contrary notwithstanding,
         the Company and the Guarantors shall not be liable for any settlement
         of any such claim or action effected without its written consent. The
         Company's indemnity agreement contained in this Section 9(a) and its
         warranties and representations contained in this Agreement shall remain
         in full force and effect regardless of any investigation made by or on
         behalf of any Initial Purchaser or controlling person, and shall
         survive any termination of this Agreement and the issuance and delivery
         of the Initial Notes.

                  (b) Each Initial Purchaser, severally and not jointly, agrees
         to indemnify and hold harmless the Company and the Guarantors and their
         respective directors, officers and controlling persons from and against
         any loss, expense, liability or claim which arises out of or is based
         upon any alleged untrue statement of a material fact contained in, and
         in conformity with information furnished in writing by or on behalf of
         such Initial Purchaser to the Company expressly for use with reference
         to such Initial Purchaser in the Preliminary Offering Memorandum or the
         Offering Memorandum, or arises out of or is based upon any alleged
         omission to state a material fact in connection with such information
         required to be stated in such documents or necessary to make such
         information not misleading. If any action is brought against the
         Company or the Guarantors or any such person in respect of which
         indemnity may be sought against any Initial Purchaser pursuant to this
         paragraph, the Company or the Guarantors or such person shall promptly
         notify such Initial Purchaser in writing or by telephone, confirmed in
         writing, of the institution of such action, and such Initial Purchaser
         shall assume the defense of such action, including the employment of
         counsel and payment of expenses; provided, however, that the failure so
         to notify such Initial Purchaser will not relieve it from any liability
         that it may have to the Company or the Guarantors under this Section
         9(b) unless, and only to the extent that, such failure results in the
         forfeiture of substantive rights or defenses by such Initial Purchaser.
         The Company or the Guarantors or such person shall have the right to
         employ its or their own counsel in any such case, but the fees and
         expenses of such counsel shall be at the expense of the Company or the
         Guarantors or such person unless the employment of such counsel shall
         have been authorized in writing by such Initial Purchaser in connection
         with the defense of such action or such Initial Purchaser shall not
         have employed counsel to have charge of the defense of such action or
         such 

                                       11

<PAGE>   13



         indemnified party or parties shall have reasonably concluded that there
         may be defenses available to it or them which are different from or
         additional to those available to such Initial Purchaser (in which case
         such Initial Purchaser shall not have the right to direct the defense
         of such action on behalf of the indemnified party or parties), in any
         of which events such fees and expenses of one counsel for all
         indemnified parties selected by the Company shall be borne by such
         Initial Purchaser. Anything in this paragraph to the contrary
         notwithstanding, no Initial Purchaser shall be liable for any
         settlement of any such claim or action effected without the written
         consent of such Initial Purchaser. The indemnity agreement on the part
         of each Initial Purchaser contained in this Section 9(b) shall remain
         in full force and effect regardless of any investigation made by or on
         behalf of the Company or the Guarantors or such person, and shall
         survive any termination of this Agreement and the issuance and delivery
         of the Initial Notes.

                  10. CONTRIBUTION. If the indemnification provided for in
Section 9 above is unavailable in respect of any losses, expenses, liabilities
or claims referred to therein, then the parties entitled to indemnification by
the terms thereof shall be entitled to contribution to liabilities and expenses
except to the extent that contribution is not permitted under Section 11(f) of
the Act. In determining the amount of contribution to which the respective
parties are entitled, there shall be considered the relative benefits received
by each party from the offering of the Initial Notes (taking into account the
portion of the proceeds of the offering received by each), the parties' relative
knowledge and access to information concerning the matter with respect to which
the claim was asserted, the opportunity to correct and prevent any misstatement
or omission, and any other equitable considerations appropriate under the
circumstances. The parties entitled to indemnification agree that it would not
be equitable if the amount of such contribution were determined by pro rata or
per capita allocation (even if the Initial Purchasers and their directors,
officers and controlling persons were treated as one entity for such purpose).
The contribution agreement contained in this Section 10 shall remain in full
force and effect regardless of any investigation made by or on behalf of any
Initial Purchaser or the Company and the Guarantors or any of their respective
directors, officers or controlling persons and shall survive any termination of
this Agreement and the issuance and delivery of the Initial Notes.

                  11. NOTICES. All statements, requests, notices and agreements
shall be in writing or by telegram or facsimile and, if to the Initial
Purchasers, shall be sufficient in all respects if delivered or sent by
registered mail to the address furnished in writing for the purpose of such
statements, requests, notices and agreements hereunder, and, if to the Company
or the Guarantors shall be sufficient in all respects if delivered or sent by
registered mail to the Company at 6225 North Highway 161, Suite 400, Irving,
Texas 75030, Attention:
General Counsel.

                  12. CONSTRUCTION. This Agreement shall be governed by, and
construed in accordance with, the internal laws of the State of New York.

                  The section headings in this Agreement have been inserted as a
matter of convenience of reference and are not a part of this Agreement.

                  13. PARTIES IN INTEREST. The Agreement herein set forth has
been and is made solely for the benefit of the Initial Purchasers and the
Company and the Guarantors, and the controlling persons, directors and officers
referred to in Sections 9 and 10 hereof, and their respective successors,
assigns, executors and administrators, and no other person shall acquire or have
any right under or by virtue of this Agreement. Nothing in this Agreement is
intended or shall be construed to give to any other person, firm or corporation
(including, without limitation, any purchaser of the Initial Notes from an

                                       12

<PAGE>   14


Initial Purchaser or any subsequent holder thereof) any legal or equitable
right, remedy or claim under or in respect of this Agreement or any provision
herein contained.

                  The term "successor" as used in this Agreement shall not
include any purchaser, as such purchaser, of any Initial Notes from any Initial
Purchaser or any subsequent holder thereof or any purchaser, as such purchaser,
of any Notes or any subsequent holder thereof.

                  14. COUNTERPARTS. This Agreement may be executed in any number
of counterparts which, taken together, shall constitute one and the same
instrument.

                            [Signature Pages follow]











                                       13


<PAGE>   15







                  If the foregoing is in accordance with your understanding of
our agreement, kindly sign and return to us the enclosed duplicate hereof,
whereupon it will become a binding agreement between the Company, the Guarantors
and the Initial Purchasers in accordance with its terms.

                                         Very truly yours,

                                         BEAR, STEARNS & CO. INC.


                                         By: /s/ TIMOTHY O'NEIL
                                            -----------------------------------
                                            Name: Timothy O'Neil
                                            Title: Senior Managing Director


                                         LEHMAN BROTHERS INC.


                                         By: /s/ C. VAN SCHELTINGER
                                            -----------------------------------
                                            Name: C. Van Scheltinger
                                            Title: Senior Vice President


                                         MORGAN STANLEY & CO. INCORPORATED


                                         By: /s/ MARK BRADLEY
                                            -----------------------------------
                                            Name: Mark Bradley
                                            Title: Principal


                                         SALOMON BROTHERS INC


                                         By: /s/ ARTHUR H. TILDESLEY, JR.
                                            -----------------------------------
                                            Name: Arthur H. Tildesley, Jr.
                                            Title: Managing Director



<PAGE>   16



The foregoing Purchase Agreement is hereby confirmed as of the date first above
written.


PROTECTION ONE ALARM MONITORING, INC.



By: /s/ JOHN W. HESSE
   -------------------------------
      Name: John W. Hesse
      Title: Chief Financial Officer, Vice
             President and Secretary



PROTECTION ONE, INC.



By: /s/ JOHN W. HESSE
   -------------------------------
      Name: John W. Hesse
      Title: Chief Financial Officer, Vice
             President and Secretary  



WESTAR SECURITY, INC.



By: /s/ JOHN W. HESSE
   -------------------------------
      Name: John W. Hesse
      Title: Secretary and Treasurer




WESTSEC, INC.



By: /s/ JOHN W. HESSE
   -------------------------------
      Name: John W. Hesse
      Title: Secretary and Treasurer



<PAGE>   17






                                   SCHEDULE I
                                   ----------
<TABLE>
<CAPTION>
Name of Initial Purchaser                                        Amount
--------------------------                                       ------
<S>                                                     <C>        
Bear Stearns & Co. Inc.                                       125,000,000
Lehman Brothers Inc.                                           50,000,000
Morgan Stanley & Co. Incorporated                              50,000,000
Salomon Brothers Inc                                           25,000,000
                                                        -----------------
         Total                                          $     250,000,000
                                                        -----------------
</TABLE>



<PAGE>   18




                                    EXHIBIT A


Protection One, Inc.

Westar Security, Inc.

WestSec, Inc.