Former FBI criminal profilers John Douglas and Robert Ressler concluded long ago that serial killers fall into one of two categories: organized people who carefully plan their crimes and “disorganized” ones who don’t chose their victims logically, writes Malcolm Gladwell in The New Yorker. “Not long ago,” Gladwell says, psychologists at the University of Liverpool tested the F.B.I.'s assumptions. The made lists of crime-scene characteristics showing organization and disorganization.
When they looked at a sample of a hundred serial crimes, they couldn't find any support for the FBI's distinction. It turns out that crimes are almost always a mixture of a few key organized traits and a random array of disorganized traits. Laurence Alison, a leader of the Liverpool group and author of “The Forensic Psychologist's Casebook,” said, “The whole business is a lot more complicated than the F.B.I. imagines.”