Suspect Profiling Case Study

We are excited to announce that the Second Edition of the Encyclopedia of Forensic and Legal Medicine will be publishing November 2015! In this pioneering four volume encyclopedia, an international team of forensic specialists explore the relationship between law, medicine, and science in the study of forensics.  This important work includes over three hundred state-of-the-art chapters, with articles covering crime-solving techniques such as autopsies, ballistics, fingerprinting, hair and fibre analysis, and the sophisticated procedures associated with terrorism investigations, forensic chemistry, DNA, and immunoassays. Available online and in four printed volumes, the encyclopedia is an essential reference for any practitioner in a forensic, medical, healthcare, legal, judicial, or investigative field looking for easily accessible and authoritative overviews on a wide range of topics. Read below about criminal Profiling, just one of the hundreds of interesting and exciting topics covered.

Criminal Profiling- Understanding the Criminal Mind

Dr. James A. Brussel, a New York psychiatrist, was one of the first practitioners of criminal profiling. For a 16-year period during the 1940s and 1950s, New York City was terrorized by the “Mad Bomber,” who set off 37 bombs in the New York area. The police contacted Dr. Brussel for an analysis of the case. Dr. Brussel concluded that the individual would be a heavy-set man, foreign-born, a Roman Catholic, and living with a sibling. He further stated that when the police located the man, he would be wearing a buttoned double-breasted suit. In 1957, George Metesky was arrested by the police for the bombings. Metesky was a heavy-set, foreign-born, Roman Catholic, who lived with his sister. When he answered the door, he was wearing a double-breasted suit, buttoned.

In the 1970s, the Federal Bureau of Investigation (FBI) began providing criminal profiling based upon a multidisciplinary approach of investigative experience, psychology, crime scene expertise, and forensics. Special Agent Howard Teten was a member of the FBI’s Behavioral Science Unit (BSU), who developed and taught a course titled Applied Criminology (profiling). Teten co-taught this course with a fellow agent, Pat Mullany, who was also an instructor at BSU. Together, they began to receive requests from police investigators to review and conduct profiles on current, ongoing cases. Their analyses met with many positive results. The success of Teten and Mullany led to the creation of the FBI’s National Center for the Analysis of Violent Crime (NCAVC) and put the process of criminal profiling into common practice.


The process of profiling has its origins in “psychological profiling” and criminal case-study descriptions originally published by forensically inclined psychologists and psychiatrists seeking to further the understanding of the criminal mind. Early profiling work also involved the psychiatric and psychological assessments of individuals for strategic purposes, such as the psychiatric assessment of Aldof Hiltler during World War II. Historically, psychiatrists and psychologists wrote psychological profiles of criminals as diagnostic formulations. Early profiling efforts were disseminated among mental-health professionals to foster discussion and debate on a broad diversity of theoretical issues. These “profiling” orientations practiced by mental-health professionals often lacked overt practical law-enforcement application.

In the 1970s, “psychological profiling,” sometimes referred to as “criminal or behavioral profiling,” was systematically implemented as an investigative technique by the BSU. The FBI’s approach to profiling differed markedly from the methodology employed by mental-health professionals. Rather than conducting a clinically based construct of a known offender as a means of gaining insight, detailed examinations of the behavior(s) evidenced in the interactions between offenders and victims, and displayed at the scenes of crimes served as the basis of analysis and prediction. The FBI approach to criminal profiling was predicated on the belief that criminal behavior, as evidenced in victim–offender interactions and crime scene activities, reflected offender personality traits and that such traits could be identified and categorized. FBI profiling began as an informal analysis, but gradually transitioned into a formal service as the practical law-enforcement value of behaviorally based crime analyses became evident. With time, research involving the interviews of incarcerated offenders, coupled with the standardization of analytical protocols and training methodologies, served to formalize the profiling process.

Early FBI criminal profiling efforts focused primarily on ascribing behavioral and personality characteristics to unknown offenders in serious violent crimes and serial offenses. Central to this approach was the concept of an organized/disorganized behavioral dichotomy. This continuum was based on recognized differences in a spectrum of behavioral characteristics indicative of varying degrees of criminal sophistication. Organized offenders planned their offenses, would target a victim who was a stranger, and were very evidence-conscious. Disorganized offenders tended to commit spontaneous offenses, were acquainted with the victim, and left physical evidence at the crime scene.

Through analysis of the crime scene, profilers could utilize crime scene characteristics to ascertain personality traits of either organized or disorganized offenders. Organized offenders were described as very intelligent, with better than average IQ scores, high birth-order status in their family, socially and sexually competent, worked in a skilled profession, were in a controlled mood during the commission of their crime, used alcohol during the crime, were very mobile, and followed the crime in the news media. Disorganized offenders were described as of average intelligence, had minimal birth-order status, were socially immature, sexually incompetent, had poor work history, were in an anxious mood during the crime, did not consume alcohol during the crime, lived near the crime scene, and had minimal interest in the news media.

This system was limited, however, because of the inherent problems of a simple two-category classification model. Human behavior is much more variable than an “either/or” choice of organized behavior/disorganized behavior. Behavior falls along a continuum between the two poles and usually displays descriptive characteristics of both organized and disorganized offenders.

This excerpt was taken from the article Criminal profiling, read more about the psychology behind criminal profiling and the CIA approach here

Related Articles from the Encyclopedia of Forensic and Legal Medicine:

Forensic Psychiatry and Forensic Psychology | Criminal Responsibility

Crime-Scene Investigation and Examination | Collection and Chain of Evidence

Mass Murder

The Second Edition of the Encyclopedia of Forensic and Legal Medicine will be publishing November 2015! Learn more about it here.

Canter – John Duffy Case Study ‘The Railway Rapist’


This is the fourth study we will be looking at from Making a Profile, as part of your OCR A2 Forensic Psychology course. It is further categorised into both ‘case study.’


The background for this study is Canter’s circle theory and the bottom up approach to profiling. It is highly recommended that you read: Mapping Murder: The Secrets of Geographical Profiling in order to fully understand circle theory.

It is also highly recommended that you read all of the previous studies in making a profile before reading this case study, ideally this case study should consolidate your knowledge.

Case Study

Between 1975 and 1986 23 women were raped aged between 15 and 32 at railway stations in and around London. Canter became interested in the case after reading reports in the Evening Standard. In the early 1980s two Police Officers were appointed to help him draw up an offender profile. Canter placed all the cases on a map and this allowed him to speculate about where the rapist might live. He categorised perpetrators as ‘marauders’ or ‘commuters.’ Depending on whether they strike from within their home base ‘marauders’ or travel away from home ‘commuters.’

Canter’s starting point for this profile was the idea that a violent crime can be seen as a transaction between at least two people and therefore it must reveal something about the way the offenders deals with people.

Canter identified two themes in regard to how the offender commits the crime.

The first theme is how the offender deals with the victim.

The second theme is how much dominance is used.

In the John Duffy case, a minimal amount of dominance was used because weaker victims were selected.

Studying the cases over four years they placed the cases on a map and overlaid year on an acetate film to reveal distinctive patterns in the locations and types of his crimes. This allowed Canter to speculate on where Duffy was likely to live. This method was later developed into his circle theory:

John Duffy was considered a Marauder.

Preliminary Profile

Physical Characteristics:

Mid to late twenties. Light Hair, about 5’9″, right-handed.


Probably semi-skilled or skilling involving weekend work or casual labour from July 1984 onwards.

His job most likely does not bring him into contact with the public.


Likely keeps himself to himself, but has one or two very close male friends and probably very little contact with women, especially in a work situation.

Has knowledge of the railway system along which the attacks happened.

Sexual Activity:

The variety of his sexual actions suggest considerable sexual experience.

Criminal Record:

He was probably arrested sometime between 24th October 1982 and January 1984 and this attack may have had nothing to do with rape, but will have been aggressive and under the influence of drink or drugs.

This was the first case to have an attempt to use behavioural characteristics to search for a criminal instead of purely forensic evidence from the crime scene. It was successful.

In November 2000 John Duffy who was serving life for the rape and murder of several women, confessed that he was responsible for many more and that he committed some of the rapes with an accomplice: David Mulcahy.

Initially, before the geographical profiling and the behavioural profiling Duffy was one of 2000 suspects, after the profiling he became one of two.

Canter’s profile of John Duffy:


+ Usefulness, profiling proofed to be useful in the apprehension of Duffy, however erroneous profiling can cause the police to miss real evidence.

– Androcentrism, only one male (two with accomplice) studied.

– Validity, Canter did not predict that there would be an accomplice.





Further Reading

Sexual Homicide: Patterns and Motives

Mapping Murder: The Secrets of Geographical Profiling

Criminal Shadows: Inside the Mind of the Serial Killer

OCR A2 Psychology Student Unit Guide: Unit G543: Forensic Psychology (Student Unit Guides)


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