Not a paedophile, but an ex-classmate (and a friend) of mine killed a man and got life without parole. The circs were horrific, it wasn't 'one punch gone wrong', self defense or anything of the sort.
We weren't best friends, but we used to hang out in the same company a lot. He was a completely normal guy. Not a trouble maker, not aggressive, but also wasn't a 'quiet and closed-off' type, wasn't bullied, nothing like that. Friendly, talkative, a normal person, got along with other people. We drifted apart after school, however.
So one night he was walking home after a party. Alone. He met another guy whom he didn't know at all and had no problem with (by his own admission). He beat him half to death, took all of his clothes off and left him in the ditch, on the side of the road. It was November. Then he proceeded to walk home. After a little while, he changed his mind, came back and continued to beat the guy until he died.
I came to know about it from newspapers. I still don't understand what the hell happened to him, why/how could he do that..