who's the killer in the book?

The killer in the book is the witness of the ATM murder James Noone (Called Lockeridge in the movie, in the book Buddy's last name is Lockeridge). Terry got him after he reviewed hypnosis session with him. While they were in the room he asked Winston couple of questions and she was just nodding, and Noone didn't answer although under hypnosis he should have answered those question because he was not aware of somebody else's presence in the interrogation room.