I think this guy is very mentally unsound. He need psychiatric help. The brain works in a strange way. It's obvious this guy's brain is not normal.
I don't know how his upbringing is. But, he seem lacking of moral. I mean, even if someone has the urge to hurt/kill in a moment of anger, his conscience and moral value will stop him.
I'm for the second chance if he's really remorseful. But, make sure he gets lots of psychiatric help and need a good thorough evaluation before letting him out to society.
If he's really remorseful, the guilt will already haunt him for live.