An important event in the development of criminal psychology as an independent discipline apart from the rest of psychology was the special report on Adolph Hitler prepared by Henry Murray, director of the Harvard Psychological Clinic, for the wartime OSS. In his report, Murray stated that Hitler suffered from Oedipal tendencies and a childhood in which he felt estranged from both of his parents. He concluded the report with an accurate prediction of Hitler's suicide.
Perhaps the first notable use of a professional psychologist in a police investigation was in 1956 with the investigation of the so called "Mad Bomber" case. New York City police consulted with the Freudian psychologist James Brussel on the profile of a perpetrator who had for years been leaving pipe bombs in public spaces. Brussel correctly predicted that he would be a man from a Slavic country and would be wearing a buttoned double-breasted suit.
In the 1970s the two FBI employed psychologists John Douglas and Robert Ressler conducted a study where they went around the United States and interviewed captured serial killers. They created a standard profile which has been used in many cases since to identify likely suspects. They divided serial killers into two broad categories---those who commit their crime impulsively and those who do it only after planning; disorganized killers and organized killers.
Notably, psychologists at the University of Liverpool have recently criticized the FBI profile as allowing for too much subjective judgment to really be reliable. The main criticism is that there is no clear line that can be drawn in any case between those crimes which seem organized and those that seem disorganized. Many cases have evidence of both. Further criticism of the discipline has focused on the ways that researchers apply very general vague terms.