Texas Government Code - GOV'T § 418.115. Requesting and Providing Mutual Aid Assistance

(a) A request for mutual aid assistance may be submitted verbally or in writing. If a request is submitted verbally, it must be confirmed in writing.

(b) If a request for mutual aid assistance is made to a department or agency of a political subdivision, the chief or highest ranking officer of the department or agency, with the approval and consent of the presiding officer of the governing body of the political subdivision or that officer's designee, may provide the requested assistance in accordance with the policies, ordinances, and procedures established by the governing body of the political subdivision.