Between 1976 and 1979, two FBI agents — Robert Ressler and John Douglas — began driving to prisons during road-school teaching trips and asking to speak to convicted murderers. There was no program, no authorization and no budget. They wanted to know why offenders did what they did, and it occurred to them that the offenders were available and nobody had asked.
They eventually interviewed thirty-six men convicted of sexual homicide, including Ed Kemper, Charles Manson, Richard Speck, David Berkowitz and Ted Bundy. The work became the Criminal Personality Research Project and produced the 1988 book Sexual Homicide: Patterns and Motives and the organized-disorganized typology that shaped criminal profiling for a generation.
What is interesting for this guide is the interview method, because these were not interrogations. Nothing could be extracted; the men were convicted and had nothing at stake. What Ressler and Douglas had to offer was something else entirely.
They offered status. An FBI agent had traveled to hear this man's account of his own life and considered him worth understanding. They offered attention, at length, from a knowledgeable listener. They offered non-judgment, which in a setting where every other interaction is condemnatory is a considerable inducement. And they demonstrated preparation — they knew the case files, which signaled that lying would be detected and that the listener was worth talking to.
That is chapter 106's elicitation applied to a captive population, and it worked for the same reasons: self-disclosure is rewarding, expertise is flattering, and a person who has been treated as a specimen for years will talk to someone who treats them as an author.
Kemper in particular is reported to have been an expansive and articulate interviewee, and the agents' accounts describe a persistent difficulty, which is worth noting as a hazard of the method: prolonged sympathetic listening to people who have done terrible things exacts a cost on the listener, and Ressler and Douglas both wrote about it.
The typology that emerged has had a harder scientific life than its cultural presence suggests. Organized versus disorganized was intended as a dichotomy of crime scenes reflecting offender characteristics. David Canter and colleagues tested it against a large sample of serial killings and found no support for the dichotomy — organized features were common to most, and disorganized features did not cluster as predicted. Laurence Alison and others have shown that profiles are frequently ambiguous enough to be judged accurate whichever offender is eventually caught, which is chapter 27's Barnum effect operating on investigators.
So the honest assessment is split. The interviews produced a large body of genuinely novel descriptive material about a rare population, and the interview technique itself is sound. The classification system built from a sample of thirty-six convicted men — selected for being caught, and interviewed without independent verification of their accounts — is not a validated instrument, and its investigative value has been consistently overstated.
Cross-ref: elicitation techniques chapter