John Douglas was the head of the FBI's investigative Support Unit until his retirement in June 1996 and is a leading expert in tracking and capturing serial killers. As the former head of the FBI's Serial Crime Unit, he conducted the first organized study into the methods and motivations of serial criminals and has aided police departments and prosecutors throughout the United States and the world. When examining a crime scene he is able to become both predator and prey and he notes things that might be overlooked by other law enforcement agents. With enough information, an experienced profiler can pick out a criminal's age, sex, race, marital status, family background, emotional state, education and general employment. The article describes how Douglas profiles victims as well as offenders and discusses profiling the profiler. Douglas is also interested in the transformation of some molesters from molestation to homicide.