Tex. Code of Criminal Procedure § 18A.202

(a) The prosecutor in a county in which an interception device is to be installed or used shall designate in writing each peace officer in the county, other than a commissioned officer of the department, who is:

(1) a member of a law enforcement unit specially trained to respond to and deal with life-threatening situations; and

(2) authorized to possess an interception device and responsible for the installation, operation, and monitoring of the device in an immediate life-threatening situation.

(b) A peace officer designated under Subsection (a) or Article 18A.301(c) may possess, install, operate, or monitor an interception device if the officer:

(1) reasonably believes an immediate life-threatening situation exists that:

(A) is within the territorial jurisdiction of the officer or another officer the officer is assisting; and

(B) requires interception of communications before an interception order can, with due diligence, be obtained under this subchapter;

(2) reasonably believes there are sufficient grounds under this subchapter on which to obtain an interception order; and

(3) before beginning the interception, obtains oral or written consent to the interception from:

(A) a judge of competent jurisdiction;

(B) a district judge for the county in which the device will be installed or used; or

(C) a judge or justice of a court of appeals or of a higher court.

(c) If a peace officer installs or uses an interception device under Subsection (b), the officer shall:

(1) promptly report the installation or use to the prosecutor in the county in which the device is installed or used; and

(2) within 48 hours after the installation is complete or the interception begins, whichever occurs first, obtain a written interception order from a judge of competent jurisdiction.

(d) A peace officer may certify to a communication common carrier that the officer is acting lawfully under this subchapter.