Some people are just too mentally sick to be let out walking free in the streets ever again.
We have seen a maniac like that here in Denmark too. While he lived in Florida with his family, he murdered his mum and buried her at the beach with help from his father no less. He served some years in prison and came back to Denmark. Some time later, he had murdered his girlfriend and her two minor sons here, and not only that: he even cut them up in pieces and throw their leftovers out somewhere, with help from his father once again...

He wasn't too cooperative towards helping the police to find the pieces, so the civil military service was sent out to find them, and I hate him forever, because I was part of that work back in 2000.
Some people should just be put in the blackest hole in a prison, and the key should be thrown away. They're scum of the Earth...