I don't get something about the killer's motive (SPOILERS)
He first meets John outside the barber shop, where he gives him the toy. In the barber shop is where Matthew is told to go talk to the construction site about a job. We can assume he hauls ass over there ASAP. He's talking to the owner, and Diploma walks by, all hot and sweaty from working.
OK, so nevermind that. During the interrogation, he says he killed him because of the burden he was too Matthew and that Matthew was his friend. John was his 1st, and if we go by what Tom said, he got a taste of it, and continued to be a child killer. So was that all a lie and he was stalking John and that's why he convinced the owner to give Matthew the job??
Still doesn't eplain how he went from a well dressed man in a hat to a hot, sweaty guy in a wife beater within minutes.