There is another option; the (presumed) thief had a gun, but the shooter or one of his buddies decided they liked it and so stole it from the corpse.
Which does make me wonder, was the person in possession of the stolen truck the thief, or had they just bought it off the original thief?
BTW is the “castle doctrine” related to “an Englishman’s home is his castle”, because you realise that was a joke right?
