If you haven't read it get yourself a copy of the book...
The Jigsaw Man by Paul Britton
Paul is a forensic psychologist employed by the police to help them identify what they are looking for in a suspect. It's compelling reading as Paul writes about all the cases he's been involved in.
You need a good stomach though as the cases are written in full detail, autopsy reports, previous histories of the criminals etc.
It contains the James Bulger case in it as well as other high profile ones from Britain in the late 80's and 90's. It is amazing to see how with little information Paul can provide a picture of exactly who the police need to look for and the accuracy of his psychological profiles is unbelievable.
You'll get it on ebay cheap. I'd lend mine out but I'm funny with books and like to keep one's that I really like!