Tex. Penal Code § 9.43
A person is justified in using force or deadly force against another to protect land or tangible, movable property of a third person if, under the circumstances as he reasonably believes them to be, the actor would be justified under Section 9.41 or 9.42 in using force or deadly force to protect his own land or property and:
(2) the actor reasonably believes that:
Acts 1973, 63rd Leg., p. 883, ch. 399, Sec. 1, eff. Jan. 1, 1974.
Amended by Acts 1993, 73rd Leg., ch. 900, Sec. 1.01, eff. Sept. 1, 1994.