Very disturbing article here about an incident in the US where a robber is killed by the person he was trying to rob. I don't have a problem with i) a man being armed or even (in theory) ii) shooting in self-defense, especially if in a home (or something like a home). I do have a problem with the robber being shot twice from behind when he was trying to run away. That just seems like murder to me.
NB South Carolina's 'castle doctrine' seems like an echo of Exodus 22.2: "If a thief be found breaking up, and be smitten that he die, there shall no blood be shed for him."