First off- Texas has an explicit law making copper and catalytic converter theft a "Jail felony"- but if you break any other laws on the way, it's upgraded to a class 3 felony. See: https://statutes.capitol.texas.gov/?tab=1&code=PE&chapter=PE... And. if you really want to play cops and robbers, a personally witnessed jail felony seems to be enough for a citzen's arrest.

Second: "(B) the use of force other than deadly force to protect or recover the land or property would expose the actor or another to a substantial risk of death or serious bodily injury." - YOU HAVE TO BE AFRAID FOR YOUR LIFE Texas gives citizens enourmous latitude in these matters, but it's not carte blanche for murder.