It is in situations like these that I'd be in favor of immediate execution. I know that sounds like vigilante justice and I get tired of "He needs to have his eyes scalded out and his gnads cut off!" comments, but obviously this guy has no impulse control and is a danger to society.
If there is no question of his guilt--confession, all that--then take him to the nearest animal control facility and put him to sleep.
This is why I will never, ever bring another man into my childrens' lives if something were to happen to my husband. When they're grown and out of the house, fine, but in the wild many males will kill the offspring of their mates if they were sired by another male. I think we see that happening all too often in human beings, and it's depressing.