Tex. Penal Code § 9.51 — TX Code / Code pe / Chapter 9 / Section 9.51
§ 9.51. ARREST AND SEARCH.
Status: in_force

(a) A peace officer, or a person acting in a peace officer's presence and at his direction, is justified in using force against another when and to the degree the actor reasonably believes the force is immediately necessary to make or assist in making an arrest or search, or to prevent or assist in preventing escape after arrest, if:

(1) the actor reasonably believes the arrest or search is lawful or, if the arrest or search is made under a warrant, he reasonably believes the warrant is valid; and

(2) before using force, the actor manifests his purpose to arrest or search and identifies himself as a peace officer or as one acting at a peace officer's direction, unless he reasonably believes his purpose and identity are already known by or cannot reasonably be made known to the person to be arrested.

(b) A person other than a peace officer (or one acting at his direction) is justified in using force against another when and to the degree the actor reasonably believes the force is immediately necessary to make or assist in making a lawful arrest, or to prevent or assist in preventing escape after lawful arrest if, before using force, the actor manifests his purpose to and the reason for the arrest or reasonably believes his purpose and the reason are already known by or cannot reasonably be made known to the person to be arrested.

(c) A peace officer is justified in using deadly force against another when and to the degree the peace officer reasonably believes the deadly force is immediately necessary to make an arrest, or to prevent escape after arrest, if the use of force would have been justified under Subsection (a) and:

(1) the actor reasonably believes the conduct for which arrest is authorized included the use or attempted use of deadly force; or

(2) the actor reasonably believes there is a substantial risk that the person to be arrested will cause death or serious bodily injury to the actor or another if the arrest is delayed.

(d) A person other than a peace officer acting in a peace officer's presence and at his direction is justified in using deadly force against another when and to the degree the person reasonably believes the deadly force is immediately necessary to make a lawful arrest, or to prevent escape after a lawful arrest, if the use of force would have been justified under Subsection (b) and:

(1) the actor reasonably believes the felony or offense against the public peace for which arrest is authorized included the use or attempted use of deadly force; or

(2) the actor reasonably believes there is a substantial risk that the person to be arrested will cause death or serious bodily injury to another if the arrest is delayed.

(e) There is no duty to retreat before using deadly force justified by Subsection (c) or (d).

(f) Nothing in this section relating to the actor's manifestation of purpose or identity shall be construed as conflicting with any other law relating to the issuance, service, and execution of an arrest or search warrant either under the laws of this state or the United States.

(g) Deadly force may only be used under the circumstances enumerated in Subsections (c) and (d).