Susan de Guardiola talked about this on her blog and I got it from the library. I thought the first two-fifths was very boring, but things do start to happen later. There's going to be two more books, but I don't plan to read them.
The protagonist, John Wayne Cleaver, is fifteen and has Antisocial Psychiatic Disorder. He sees a psychiatrist every week to try to keep his own killer inside. He builds rules into a wall so he won't hurt anybody. The town has three deaths and at first John thinks it's a serial killer, but then he realizes who the killer is. He gives an anonymous tip to the police and both officers who turn up are killed. This is when he lets his wall down and his monster out, so he can kill the bad guy.
It was okay, but not my thing. Susan liked it a lot more, so you might want to click on the link above and read her review.