yeah, that's murder in most states. Morally/ethically though, I don't really have a problem with killing bandits one way or the other. If it were legal in my state, I would have done the same thing. Do you assume a bandit has a problem with shooting you in the back? Do you think soldiers don't get shot in the back all the time? Do you think LEOs don't shoot fleeing suspects in the back? If you are going to fight with monsters, you have to be prepared to become a monster. with apologies to Mr. Nietzsche .
Aw jeez, you are right!
I would never shoot anyone in the back, especially if they were carrying my stuff! The 10mm tends to overpenetrate.