John Douglas, Criminal profiler John Douglas worked for the FBI's Investigative Support Unit for 25 years. He is an Air Force veteran and doctor of education and has written or coauthored more than 100 criminology texts and research papers. In his study of the criminal mind, Douglas interviewed convicted murders, rapists, kidnappers and assassins that included Charles Manson, Sirhan Sirhan, Richard Speck, John Wayne Gacy, David Berkowitz, James Earl Ray and Ted Bundy, to name a few. Through this research, he learned how criminals think, and to see the world, the victims and the crime scenes through their eyes as well as perfected the art of psychological profiling to catch serial killers.… The Scott Glenn character in The Silence of the Lambs was based on Douglas, and he consulted on the film. "Mind Hunter: Inside the FBI's Elite Serial Crime Unit," which is co-written with Mark Olshaker, is a psychological study that tells the real life story of the Investigative Support Unit of the FBI and the country's most notorious serial killers. It's a memoir of Douglas' time with the FBI and shows how this special force assisted state and local police in solving some of the most celebrated serial murder and rape cases. Olshaker and Douglas' first fictional work together was "Broken Wings." It tells how former profiler Jake Donovan and a special team of former agents investigate the apparent suicide of the director of the FBI. Also written with Olshaker were the titles "The Anatomy of Motive," "Obsession," and "Journey into Darkness." "Sexual Homicide: Patterns and Motives" was written with Robert K. Kessler and Ann W. Burgess, both former FBI agents. These three authors, along with Allen G. Burgess, also wrote "Crime Classification Manual," which classifies the three major felonies of murder, arson and sexual assault and standardizes the language and terminology used throughout the criminal justice system.