The Art of Forensic Psychology
When Dennis Rader was arrested in 2005 during the investigation for the BTK killer who had been operating in Wichita, Kansas since 1974, the media buzzed about whether he fit the "profile" of a typical serial killer. Reporters had the idea of a criminal profile all wrong. It's not a blueprint, as they often suggested, against which people can be measured to see how they do or do not fit. It's a list of suggested behaviors and traits derived from the specific behavior evident at a crime scene or series of crime scenes that helps to narrow down leads and diminish the potential pool of suspects.
Within the past two decades, there has been increased use of profiling, although it remains a controversial tool. Not everyone believes that devising a hypothetical portrait of a suspect makes a contribution to solving crimes, but some profiles have been surprisingly accurate. The problem is that it's difficult to know when you're working with a good one until the suspect is caught and compared against it.
Profiling has been developed in the FBI's Behavioral Science Unit (a.k.a. Investigative Support Unit) by such people as John Douglas (Mindhunter), Robert Ressler (Whoever Fights Monsters), and Roger DePue (Between Good and Evil). However, it is also used by police departments all over the country -- especially those with officers trained at the National Academy -- as a tool in their crime-fighting arsenal. The basic idea for a profile is to gather a body of data yielding common patterns so that investigators can develop a general description of an UNSUB (unknown suspect). Profiling involves the psychology-trained expert using his or her knowledge in human behavior, motivation, and patterns of pathology to create a multidimensional report.
A profile is based on the idea that people tend to be guided by their individual psychology and will inevitably leave idiosyncratic clues. Are they male or female? Geographically stable or transient? Impulsive or compulsive? From a crime scene, a profiler can assess whether the person is an organized predator as opposed to having committed an impulsive crime of opportunity. They may also observe if the offender used a vehicle, exhibits criminal sophistication, or is addicted to a sexual fantasy.
Developing a profile works best off evidence of psychopathology, such as sadistic torture, postmortem mutilation, or pedophilia. Some killers leave a "signature"--a behavioral manifestation of a personality quirk, such as staging the corpse for the most humiliating exposure or tying ligatures with a complicated bow. This helps to link crime scenes with one another and to alert law enforcement officers of the presence of a serial rapist, bomber, arsonist, or murderer. It may also help, if a pattern is detected, to predict future possible attacks, likely pick-up or dump sites, and victim type.
Profiling is not just a personality assessment, but includes other types of data. Coming up with estimates about an UNSUB's age, race, sex, occupation, educational level, social support system, MO, type of employment, and other sociological factors are just as important as evidence of a personality disorder. It's also important to include a geo-forensic analysis of the kind of place a killer might chose as a body dump site, such as Ted Bundy's preference for heavily wooded mountains outside Seattle and Arthur Shawcross's dumpsites near New York state's Genesee River Gorge.
The best profilers have gained their knowledge from experience with criminals and have developed an intuitive sense about certain types of crime. Generally, profilers employ psychological theories that provide ways to analyze mental deficiency such as delusions, personality characteristics like hostility, criminal thought patterns, and character defects. They also need to know about actuarial data such as the age range into which offenders generally fall and how important an unstable family history is to criminality. This database changes with new information, and that in turn influences how a profile may be developed. With increasingly more representatives from different racial groups and more women becoming serial offenders, the predictions about the UNSUB will shift to accommodate this data.
And there are other types of consulting roles for forensic psychologists as well.