Jeff was a 13 year old boy who killed his family. It's not that much of a stretch from reality.
I've read about how an 8 year old girl who tutored kids by sticking pins in their skin. It's not that uncommon to hear about a kid who has murdered before. And psychopathy can start at a very early age also. Or maybe Jeff had a chemical imbalance. We'll never know, but just keep this in mind.
