I think the clerk's problem is, an employee, it was not his personal property.
From an actual Texas lawyer's website:
Texas Law - Deadly Force Defense of Property - CCW Safe National | CCW Safe Weapon Liability | CCW Safe Defense Attorneys
Look up the case of Joe Horn. Shot a thief crawling out his neighbors window. After that my neighbors and I all gave each other written permission to defend each others homes. We called it the "Joe Horn Rules".
As a sidebar Joe Horn got off but it totally ruined his life.
A little more to the Joe Horn case.
Two guys were burglarizing his neighbors house in broad daylight.
Joe called 911 to report it.
The 911 operator told him to stay inside help was on the way.
Joe said he was going to stop it. And you could hear him rack a shell in his shotgun.
He went out in his front yard.
The two burglars came into his yard.
Hot shot both of them and they died in his yard.
A plain cloths officer was putting on his vest and saw everything happen.
The local community activists cried to high Heaven.
Judge, Jury, executioner etc.
The Grand Jury no billed him.
Happened not far from me. I know some of his neighbors.
It was very costly for him. Finally moved away.
As a note the robbers were unarmed. But the only way anyone could tell would be if they were naked. So he did not know for sure.