If you are indeed robbing someone and are shot during the robbery, fuck you if you die (this guy didn't), deprived of trial, no fucks given. If you survive your wound, than you have your rights like anyone else. The law says you can't shoot someone attempting to escape , since they would no longer pose an immediate threat to you, near regardless of what they did to you in the moments prior. That doesn't mean a case won't get thrown out, your peers won't nullify, or that you would even be charged at all depending on the circumstances.
In this case a man claims he was getting out of his car, was robbed at gunpoint, and at some point the victim of the robbery shot the robber, then the robber ran away. Later in the evening someone turned up at the hospital with a gunshot wound. If these people are one in the same (all signs point to yes), he did in fact attempt to rob the victim (had no business on the residence, was not family, friend, or foe), and is not shot in the back, then we as a society should give the benefit of the doubt to the victim, barring any real evidence proving otherwise. Even if he was shot in the back I personally wouldn't care, but I could see one getting in legal trouble.