In England now, self defense is a crime. Killing in self defense is a much more serious crime than whatever the killed criminal might have been attempting. The Left is trying to bring that to the USA and if they win in November they will, probably during 2017.
Time for "shoot, shovel, and shut up". Self-defense is a God-given right, the one from which our Second Amendment rights derive. For that man to be punished for killing a predator who was attacking his wife would be unacceptable. If it happens again, I hope he will choke the thug out and rent a wood-chipper, or burn the body piece by piece over a campfire, or dissolve it in lye, or . . . . If the attacker was a stranger, no one would have any reason to look for the criminal's body at any location connected with the victims.