Technically he is, until proven guilty.. and the same applies to the "third mover" who allegedly shot the 3 robbery suspects...
I'll also note that all 3 suspects were stuck with bullets, pistols just aren't as lethal as the movies make them out to be... I think the shooter did well- made sure the suspects needed medical attention so they couldn't just flee and disappear.
And more to the point- he stopped the threat to his life.