[mvpel]

As multiple posts show, in Texas you can use deadly force to defend someone else’s property. That law predated the “castle doctrine”, which addressed a different problem.

Yes, it's true, but ONLY IF:

The other guy ASKED you to defend said property, AND

the deadly force is IMMEDIATELY necessary to prevent escape, and you reasonably believe there is NO OTHER alternative than deadly force, or that using anything LESS than deadly force would pose a serious risk to your safety.

"Boom, you're dead" doesn't sound like the words of a man who fears for his life and safety or has no other alternative to halt the escape than to pull the trigger, it sounds like a line from a B-grade action flick.

And I doubt it'll play well with a jury.

[NoGrayZone]

Depends who’s on the jury.

[achilles2000]

Please note the final “or”. There is no requirement that you have been asked to protect the property, etc.

§ 9.43. PROTECTION OF THIRD PERSON’S PROPERTY. 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:
(1) the actor reasonably believes the unlawful
interference constitutes attempted or consummated theft of or
criminal mischief to the tangible, movable property; or

[FreedomCalls]

Yes, it's true, but ONLY IF: The other guy ASKED you to defend said property

Not true. That's an "OR" provision of 9.43 where it says you can use deadly force to defend someone else's property if:

(1) the actor reasonably believes the unlawful interference constitutes attempted or consummated theft of or criminal mischief to the tangible, movable property; or

(2) the actor reasonably believes that: (A) the third person has requested his protection of the land or property