Texas Government Code - GOV'T § 614.063. Polygraph Examination

(a) A peace officer may not be suspended, discharged, or subjected to any other form of employment discrimination by the organization employing or appointing the peace officer because the peace officer refuses to submit to a polygraph examination as part of an internal investigation regarding the conduct of the peace officer unless:

(b) Subsection (a)(1) does not apply if the complainant is physically or mentally incapable of being polygraphed.

(c) For the purposes of this section, a person passes a polygraph examination if, in the opinion of the polygraph examiner, no deception is indicated regarding matters critical to the matter under investigation.

(d) The head of the law enforcement organization that employs or appoints a peace officer may require the peace officer to submit to a polygraph examination under this subsection if:

(e) The head of the law enforcement organization that employs or appoints a peace officer may require the peace officer to submit to a polygraph examination under this subsection if the head of the law enforcement organization considers the circumstances to be extraordinary and the head of the law enforcement organization believes that the integrity of a peace officer or the law enforcement organization is in question.  The head of the law enforcement organization shall provide the peace officer with a written explanation of the nature of the extraordinary circumstances and how the integrity of a peace officer or the law enforcement organization is in question.