I truly hope that he gets his just rewards, preferably by trying to do it again and being eaten by the crocodile. He's obviously psychotic, to the point in making this sound like the backstory to another Hannibal Lecter. They should look beyond his age and notice that he's mentally unstable before he gravitates to human lives, him and his brother.
The parents should probably be sterilized, too, or put into a research lab. They're apparently very good at spawning monsters, and they could be the cure to finding the murderer gene. Whatever would keep them from screwing up at parenting again, I'm for.