If the second crook was running or attempting to run away, shooting him (esp in the back) would be murder, and charges probably would have been applied. When he's running away or trying to, the threat has ended. Your adrenaline is still pumping and you want to avenge your family, *BUT* the threat has ended. YRMV. IMHOChalk one up for the right to defend yourself and family. He should have shot the other bastard Too.