Former FBI agent John Douglas, the inventor of criminal profiling, leads a journey into the minds of the 20th Century's most notorious killers, including Charles Manson, John Wayne Gacy, and... Read allFormer FBI agent John Douglas, the inventor of criminal profiling, leads a journey into the minds of the 20th Century's most notorious killers, including Charles Manson, John Wayne Gacy, and Jeffrey Dahmer.Former FBI agent John Douglas, the inventor of criminal profiling, leads a journey into the minds of the 20th Century's most notorious killers, including Charles Manson, John Wayne Gacy, and Jeffrey Dahmer.