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Offender profiling, also known as criminal profiling, is a behavioral and investigative tool that is intended to help investigators to accurately predict and profile the characteristics of unknown criminal subjects or offenders. Offender profiling is also known as criminal profiling, criminal personality profiling, criminological profiling, behavioral profiling or criminal investigative analysis. Geographic profiling is another method to profile an offender. Television shows such as Law & Order: Criminal Intent, Profiler in the 1990s, the 2005 television series Criminal Minds, the 2011 one season television series Criminal Minds: Suspect Behavior, and the 1991 film The Silence of the Lambs have lent many names to what the FBI calls "criminal investigative analysis".
Holmes and Holmes (2008) outline the three main goals of criminal profiling:
- The first is to provide law enforcement with a social and psychological assessment of the offender;
- The second goal is to provide law enforcement with a "psychological evaluation of belongings found in the possession of the offender" (p. 10);
- The third goal is to give suggestions and strategies for the interviewing process.
Ainsworth (2001) identified that there are four main approaches to offender profiling:
- The geographical approach, in which the patterns are analyzed in regard to timing and location of the crime scene, in order to determine where the offender lives and works
- Investigative psychology, this approach focuses on the use of psychological theories of analysis to determine the characteristics of the offender by looking at the presented offending behavior and style of offense
- The typological approach looks at the specific characteristics of the crime scene to then categorize the offender according to the various ‘typical’ characteristics
- The clinical approach to offender profiling in which the understanding of psychiatry and clinical psychology is used to determine whether the offender is suffering from mental illness of various psychological abnormalities
5 Procedural steps in generating a profile:
- 1. A thorough analysis of the type/nature of the criminal act is made and it is then compared to the types of people who have committed similar crimes in the past
- 2. An in depth analysis of the actual crime scene is made
- 3. The victim’s background and activities are analyzed, to look for possible motives and connections
- 4. The possible factors for the motivation of the crime are analyzed
- 5. The description of the possible offender is developed, founded on the detected characteristics, which can be compared to with previous cases
In modern criminology, offender profiling is generally considered the "third wave" of investigative science:
- the first wave was the study of clues, pioneered by Scotland Yard in the 19th century;
- the second wave was the study of crime itself (frequency studies and the like);
- this third wave is the study of the psyche of the criminal.
Offender profiling is a method of identifying the perpetrator of a crime based on an analysis of the nature of the offense and the manner in which it was committed. Various aspects of the criminal's personality makeup are determined from his or her choices before, during, and after the crime. This information is combined with other relevant details and physical evidence, and then compared with the characteristics of known personality types and mental abnormalities to develop a practical working description of the offender.
Psychological profiling may be described as a method of suspect identification which seeks to identify a person's mental, emotional, and personality characteristics (as manifested in things done or left at the crime scene). This was used in the investigation of the serial murders committed by Ted Bundy. Dr. Richard B. Jarvis, a psychiatrist with expertise on the criminal mind, predicted the age range of Bundy, his sexual psychopathy, and his above average intellect.
A further, more detailed example of how psychological profiling may be performed is the investigation of Gary Leon Ridgway, also known as the Green River Killer. This case also demonstrates the potential for incorrect predictions. John E. Douglas, an investigator who worked for the FBI, provided a twelve-page profile, which stated the suspect was:
- Probably a white male who had a dysfunctional relationship with women.
- Organized since he tried to hide the bodies and appeared to spend some time at the river
- Cunning in using rocks to weigh the victims down in the water to conceal them.
- Very mobile with a vehicle.
- Going to kill again.
- Like other serial killers, he would be prone to contacting police wanting to help in the investigations.
However, the profile created for Ridgway also revealed characteristics that did not apply to him, such as being an outdoorsman and being incapable of closeness to other people. Ridgway was not an outdoorsman, but frequented the Green River with one of his wives, and also had a very close relationship with his last wife, which contradicted the point in the profile of being incapable of closeness.
One type of criminal profiling is referred to as linkage analysis. Gerard N. Labuschagne (2006) defines linkage analysis as "a form of behavioral analysis that is used to determine the possibility of a series of crimes as having been committed by one offender." Gathering many aspects of the offender’s crime pattern such as modus operandi, ritual or fantasy-based behaviors exhibited, and the signature of the offender help to establish a basis for a linkage analysis. An offender’s modus operandi is his or her habits or tendencies during the killing of the victim. An offender’s signature is the unique similarities in each of his or her kills. Mainly, linkage analysis is used when physical evidence, such as DNA, cannot be collected.
Labuschagne states that in gathering and incorporating these aspects of the offender’s crime pattern, investigators must engage in five assessment procedures: (1) obtaining data from multiple sources; (2) reviewing the data and identifying significant features of each crime across the series; (3) classifying the significant features as either MO and/or ritualistic; (4) comparing the combination of MO and ritual/fantasy-based features across the series to determine if a signature exists; and (5) compiling a written report highlighting the findings.
The origins of profiling can be traced back to as early as the Middle Ages, with the inquisitors trying to "profile" heretics. Jacob Fries, Cesare Lombroso, Alphonse Bertillon, Hans Gross and several others realized the potential[clarification needed] of profiling in the 19th century although their research is generally considered to be prejudiced, reflecting the biases of their time.
The first offender profile was assembled by detectives of the Metropolitan Police on the personality of Jack the Ripper, a serial killer who had murdered a series of prostitutes in the 1880s. Police surgeon Thomas Bond was asked to give his opinion on the extent of the murderer's surgical skill and knowledge. Bond's assessment was based on his own examination of the most extensively mutilated victim and the post mortem notes from the four previous canonical murders.
In his notes, dated November 10, 1888, he mentioned the sexual nature of the murders coupled with elements of apparent misogyny and rage. Dr. Bond also tried to reconstruct the murder and interpret the behavior pattern of the offender: soon he came up with a profile or signature personality traits of the offender to assist police investigation. The profile said that five murders of seven in the area at the time the report was written had been committed by one person alone who was physically strong, composed, and daring. The unknown offender would be quiet and harmless in appearance, possibly middle-aged, and neatly attired, probably wearing a cloak to hide the bloody effects of his attacks out in the open. He would be a loner, without a real occupation, eccentric, and mentally unstable. He might even suffer from a condition called Satyriasis, a sexual deviancy that is today referred to as hypersexuality or promiscuity. Bond also mentioned that he believed the offender had no anatomical knowledge and could not be a surgeon or butcher. Bond's basic profile was:
“The murderer must have been a man of physical strength and great coolness and daring…subject to periodic attacks of homicidal and erotic mania. The characters of the mutilations indicate that the man may be in a condition sexually, that may be called Satyriasis”
In 1912, a psychologist in Lackawanna, New York delivered in lecture in which he analyzed an unknown criminal who was suspected of having murdered a local boy named Joey Joseph. Based on the postcards which had been used to taunt the Lackawanna Police and the Joseph family, the profile ultimately led to the arrest and conviction of J. Frank Hickey.
A version of profiling is thought to have been used in the 1940s, when investigations relied on mental health professionals to create a profile of an offender in order to aid the police investigation. Soon after, as discussed below, James Brussel was called upon to analyze the information on the Mad Bomber in New York City, and he created an accurate profile of the offender. This caught the attention of the FBI, who then worked to develop a technique for profiling, based on the process used by Brussel.
Walter C. Langer
In 1943, Major General William J. Donovan, chief of the US Office of Strategic Services (OSS), asked Dr. Walter C. Langer, a psychoanalyst based in Boston, to develop a "profile" of Adolf Hitler. What the OSS wanted was a behavioral and psychological analysis of how Hitler might behave if the war turned against him.
Dr. Langer used speeches, Hitler's book Mein Kampf, interviews with people who had known Hitler, and some four hundred published works to complete his wartime report, which was eventually declassified by OSS and published by Langer (along with certain collateral material) as The Mind of Adolf Hitler in 1972. This work contains a profile of possible behavioral traits of Hitler, and his possible reactions to the idea of Germany losing World War II. Dr. Langer’s profile noted that Hitler was meticulous, conventional, and prudish about his appearance and body. He was robust and viewed himself as a standard-bearer and trendsetter. He had manic phases, yet took little exercise. Due to a lack of evidence, Langer believed that Hitler was in reasonably good health, so it was unlikely he would die from natural causes, but he was deteriorating mentally. He would not try to escape to a neutral country, nor would he (in Langer's opinion) allow himself to be captured by the Allies. Hitler always walked diagonally from one corner to another when crossing a room, and he whistled a marching tune. He feared syphilis and germs.
Langer's profile also pointed out Hitler's oedipal complex, with the effect being the need to prove his manhood to his mother, and his masochistic coprolagnia and urolagnia. He detested the learned and the privileged, but enjoyed classical music, vaudeville, and Richard Wagner's opera. He showed strong streaks of sadism and liked circus acts that were risky and dangerous. He tended to speak in long monologues rather than have conversations. He had difficulty establishing close relationships with anyone. Since he appeared to be delusional, it was possible that his psychological structures would collapse in the face of imminent defeat. The most likely scenario was that he would commit suicide, although there was a possibility that he would order a henchman to perform euthanasia.
James A. Brussel
Between 1940 and 1956, a serial bomber terrorized New York City by planting bombs in public places including movie theaters, phone booths, Radio City Music Hall, Grand Central Terminal, and Pennsylvania Station. In 1956, the frustrated police requested a profile from Greenwich Village psychiatrist James A. Brussel, who was New York State's assistant commissioner of mental hygiene. Dr. Brussel studied photographs of the crime scenes and analyzed the so-called "mad bomber’s" mail to the press. Soon he came up with a detailed description of the offender. In his profile, Dr. Brussel suggested that the unknown offender would be a heavy middle-aged man who was unmarried, but perhaps living with a sibling. Moreover, the offender would be a skilled mechanic from Connecticut, who was a Roman Catholic immigrant and, while having an obsessional love for his mother, would harbour a hatred for his father. Brussel noted that the offender had a personal vendetta against Consolidated Edison, the city’s power company; the first bomb targeted its 67th Street headquarters. Dr. Brussel also mentioned to the police that, upon the offender's discovery, the "chances are he will be wearing a double-breasted suit. Buttoned."
From his profile, it was obvious to the police that the mysterious bomber would be a disgruntled current or unhappy former employee of Con Ed. The profile helped police to track down George Metesky in Waterbury, Connecticut; he had worked for Con Ed in the 1930s. He was arrested in January 1957 and confessed immediately. The police found Brussel’s profile most accurate when they met the heavy, single, Catholic, and foreign-born Metesky. When the police told him to get dressed, he went to his bedroom and returned wearing a double-breasted suit, fully buttoned, just as Dr. Brussel had predicted. However, Malcolm Gladwell has written that offender profiling is not a science at all, but is couched in such ambiguous language that it can support almost any interpretation; and about Brussel says:
Brussel did not really understand the mind of the Mad Bomber. He seems to have understood only that, if you make a great number of predictions, the ones that were wrong will soon be forgotten, and the ones that turn out to be true will make you famous. The Hedunit is not a triumph of forensic analysis. It’s a party trick.
Dr. Brussel assisted New York City police from 1957 to 1972 and profiled many crimes, including murder. Dr. Brussel also worked with other investigative agencies. Brussel’s profile led the Boston Police to the apprehension of Albert DeSalvo, the notorious serial sex murderer known as the Boston Strangler. The media dubbed Dr. Brussel as "Sherlock Holmes of the Couch".
Howard D. Teten, a veteran police officer from California, joined the FBI in 1962. He was appointed as an instructor in applied criminology at the old National Police Academy in Washington, D.C. Teten was greatly interested in the application of offender profiling, and had included some of the ideas in his applied criminology course. He met Dr. Brussel and exchanged investigative ideas and psychological strategies in profiling crimes. Although Teten disagreed with Dr. Brussel's Freudian interpretations, he accepted other tenets of his investigative analysis.
In 1972 the FBI’s Behavioral Science Unit at Quantico was formed, with Teten joining FBI Instructor Patrick J. Mullany's team. Teten and Mullany designed a method for analyzing unknown offenders in unsolved cases. The idea was to look at the behavioral manifestations at a crime scene for evidence of mental disorders and other personality traits, thus aiding the detectives' deductive reasoning. Their ideas on offender profiling were tested when a seven-year-old girl was abducted from a Rocky Mountains campsite in Montana in June 1973. The girl was abducted from a tent in the early hours; the offender overpowered her before she could alert her parents, who were sleeping nearby. When an intensive search for the missing child failed, the case was referred to the FBI.
Teten, Mullany and Col. Robert K. Ressler employed their criminal investigative analysis technique to track down the unknown offender. Their profile declared that the abductor was most likely a young, white, male, homicidal Peeping Tom; a sex killer who mutilates his victim after death, who sometimes takes body parts as souvenirs. Later, the profile led to the arrest of David Meirhofer, a local 23-year-old single man who was also a suspect in another murder case. The search of his house unearthed "souvenirs"—body parts taken from both victims. Meirhofer was the first serial killer to be caught with the aid of the FBI's new investigative technique, called offender profiling or criminal investigative analysis. A decade later, the technique became a more sophisticated and systematic profiling tool known as the Criminal Investigative Analysis Program (CIAP).
Richard Walter and Bob Keppel
In 1974, homicide detective Robert D. Keppel used new methods of psychological profiling to investigate notorious serial killers Ted Bundy and the Green River Killer. He combined his field expertise with criminal psychologist Richard Walter. As a psychologist in Michigan's notorious prison system, Walter had interviewed over two thousand murderers, sex-offenders and serial killers. Walter began to see common threads among offenders and was able to group all killings and sex crimes into four distinct "subtypes": power-assertive, power-reassurance, anger-retaliatory, and anger-excitation or sadism. He was the first to develop a matrix using suspect pre-crime, crime and post-crime behaviors as a tool for investigation. Walter later co-founded the Vidocq society, an exclusive organization of forensic professionals who solve cold cases for law enforcement agencies, worldwide. Together, Keppel and Walter created the HITS (Hunter Integrated Telemetry System) database, which lists characteristics of violent crimes so that common threads can be investigated. They also published a leading scholarly article for the FBI and violent crime investigators all over the world: "Profiling Killers: A Revised Classification Model for Understanding Sexual Murder".
John Douglas and Robert Ressler
In 1978, after Howard Teten left the Behavioral Science Unit, John Douglas and Robert Ressler became pillars of offender profiling in the FBI. They spent much time studying convicted sex murderers and interviewing them, creating organized and disorganized typology, which is still in use today. Ressler was also responsible for the founding of the National Center for Analysis of Violent Crime (NCAVC) and at least partially responsible for the establishment of VICAP. Their studies provide more information on the behavioral patterns, traits and characteristics of criminals which can then be added to the offender profiling program.
In 1986, police forces across the south of England were struggling to find the Railway Rapist who was then renamed the Railway Killer after murdering a victim for the first time. Dr. David Canter, a psychologist and criminologist then from Surrey University, was invited to compose British crime's first offender profile. When John Duffy was later arrested, charged and convicted, it turned out 13 of Canter's 17 proclamations about the perpetrator were accurate. Profiling became commonplace in large-scale police searches afterwards. David Canter came up with an equation that summarizes the principal research question in profiling: A ⇒C. Canter defines ‘A’ as representing all actions that occur in a crime or that are related to a crime; ‘C’ represents the characteristics of the offender; ‘⇒’ represents the scientific modeling that allows for inferences to be established regarding the characteristics from the actions
Phases of profiling
According to Gregg O. McCrary, the basic premise is that behavior reflects personality. In a homicide case, for example, FBI profilers try to collect the personality of the offender through questions about his or her behavior at four phases:
- Antecedent: What fantasy or plan, or both, did the murderer have in place before the act? What triggered the murderer to act some days and not others?
- Method and manner: What type of victim or victims did the murderer select? What was the method and manner of murder: shooting, stabbing, strangulation or something else?
- Body disposal: Did the murder and body disposal take place all at one scene, or multiple scenes?
- Post-offense behavior: Is the murderer trying to inject himself into the investigation by reacting to media reports or contacting investigators?
A sexual crime is analyzed in much the same way (bearing in mind that homicide is sometimes a sexual crime), with the additional information that comes from a living victim. Professor David Canter is the pioneer of scientific offender profiling, developing the discipline of Investigative Psychology as a response to his dissatisfaction with the scientific bases for this activity. The IAIP of which Canter is President now seeks to set professional guidelines for practice and research in this area.
Another phase of criminal profiling (crime scene investigation) is case linkage. According to Brent E. Turvey, case linkage or linking analysis refers to the process of determining whether or not there are discrete connections between two or more previously unrelated cases through crime scene analysis. It involves establishing and comparing the physical evidence, victimology, crime scene characteristics, modus operandi (MO)-organized or disorganized typologies-, and signature behaviors between each of the cases under review. It has two purposes:
- To assist law enforcement with the application of its finite resources by helping to establish where to apply investigative efforts
- To assist the court in determining whether or not there is sufficient behavioral evidence to suggest a common scheme or plan in order to address forensic issues, such as whether similar crimes may be tried together or whether other crimes may be brought in as evidence.
With respect to behavioral evidence, case linkage efforts have most typically hinged on three concepts:
There are major problems with offender profiling that have been identified.
Incorrect information from profiling can lead to false positives or false negatives. Investigators may find a suspect who appears to fit an incorrect profile and ignore or stop investigating other leads. For example, Richard Jewell was wrongly investigated (and attacked in the media) following the Centennial Olympic Park bombing in Atlanta. This not only caused great distress to Jewell, but delayed identifying the true culprit, Eric Robert Rudolph. This was a false positive: the profile identified Jewell as the offender when in fact he was not. The opposite of the false positive is the false negative: the profile yields incorrect information which would cause investigators to ignore a suspect who is actually guilty. For example, in the Beltway sniper attacks, the offender profile indicated that the killer was probably a white male in his thirties from the DC area acting alone— in fact, the crimes were perpetrated by two black males, one of whom was 41 and the other 17 years old, from the west coast of the U.S.
The Peggy Hettrick murder case is controversial because it is the only documented case of an individual having been convicted due to a reversed engineered false profile and the erroneous testimony of the psychologist who developed the profile. In 1999, a jury convicted Timothy Masters of the 1987 killing of Peggy Hettrick. Masters spent over 9 years in a Colorado prison before his release on January 22, 2008. Timothy Masters was arrested and convicted of sexual murder based on the testimony of a forensic psychologist while the opinion of a Robert R. "Roy" Hazelwood, a retired FBI criminal investigative analyst was ignored. The forensic psychologist developed a psychological profile of a killer using narrative and drawings made by Masters to conclude that Masters’ supposed fantasy was the motive and behavioral preparation for the sexual murder, regardless of the fact that the forensic psychologist knew that there was no direct or physical evidence linking Masters to the crime. The cautionary lesson in the Masters case is what happens when forensic psychologists advance opinions about criminal matters based on the extrapolation of academic research on psychological concepts involving sexual homicide cases and reject the opinions of professional criminal profilers who incorporate law enforcement analysis coupled with criminal evidentiary considerations into their work.
Some experts in criminal psychology such as Brent Turvey, as quoted by journalist Malcolm Gladwell in The New Yorker have questioned its scientific validity. Many profilers and FBI agents are not psychologists, and some researchers who looked at their work found methodological flaws.
Three psychologists from the Universities of Liverpool and Hull are questioning the basic presumption that you can draw conclusions about a person from a single instance of behaviour under such special circumstances. "The notion that particular configurations of demographic features can be predicted from an assessment of particular configurations of specific behaviors occurring in short-term, highly traumatic situations seems an overly ambitious and unlikely possibility. Thus, until such inferential processes can be reliably verified, such claims should be treated with great caution in investigations and should be entirely excluded from consideration in court."
Active profiling as allowed by the Department of Justice includes covert alteration of the environment to observe the responses of a suspect. This can be used to check whether the suspect's behavior fits the profile, but risks being labeled as police harassment or entrapment.
Popular use of the term criminal profiler has led to the proliferation of many self-described profilers offering their purported expert opinions on cable news shows in response to incidents capturing national attention in the United States. Such individuals usually have degrees in criminal justice or psychology but lack any law enforcement experience, or vice versa.
- Racial profiling
- Behavioral Analysis Unit
- Thomas Bond (British physician)
- FBI method of profiling
- Forensic profiling
- Forensic psychology
- Investigative psychology
- Richard N. Kocsis, Applied criminal psychology: a guide to forensic behavioral sciences, Charles C Thomas Publisher, 2009, pp.226
- Holmes, R. M., & Holmes, S. T. (2008). Profiling Violent Crimes: An Investigative Tool (4 ed.). Thousand Oaks: Sage Publications, Inc.
- Sammons, A. In What is Offender Profiling? (chap. Criminal Psychology) Retrieved Apr. 13, 2013, from http://www.psychlotron.org.uk/newResources/criminological/A2_AQB_crim_whatIsProfiling.pdf
- Fulero, S. M, & L. Wrightsman. (2009). Forensic Psychology. (3rd Edition, Ed.). Belmont, CA: Wadsworth.
- Criminal profiling helps investigators examine evidence from crime scenes and victim and witness reports to develop an offender description. These descriptions may include the analysis of psychological variables such as personality and behavior patterns, as well as demographic variables such as age, race or geographic location. Investigators should use profiling as a means to narrow down the suspect pool, or in structuring an interrogation of a suspect once apprehended.Criminal Profiling: An Introduction to Behavioral Evidence Analysis, by Brent Turvey, M.S. San Diego, Academic Press, 1999.
- Criminal Investigation, by Bruce Berg, 2008, 4th edition.
- The Stranger Beside Me, by Ann Rule, 1980.
- Guillen, Tomas. Serial killers issues explored through the Green River murders. Upper Saddle River, N.J: Pearson Prentice Hall, 2006. Print.
- Levi-Minzi, Micol; Shields, Maria (2007). "Serial sexual murderers and prostitutes as their victims: Difficulty profiling perpetrators and victim vulnerability as illustrated by the Green River case". Brief Treatment and Crisis Intervention 7: 77–89.
- Labuschagne, G.N. (2006). "The use of linkage analysis as evidence in the conviction of the Newcastle serial murder, South Africa", Journal of Investigative Psychology & Offender Profiling, 3(3), 183-191. doi:10:1002/jip.51
- Evans and Rumbelow, pp. 186–187; Evans and Skinner, The Ultimate Jack the Ripper Sourcebook, pp. 359–360
- Letter from Thomas Bond to Robert Anderson, 10 November 1888, HO 144/221/A49301C, quoted in Evans and Skinner, The Ultimate Jack the Ripper Sourcebook, pp. 360–362 and Rumbelow, pp. 145–147
- Canter, D. (2004). Offender Profiling and Investigative Psychology. Journal of Investigative Psychology and Offender Profiling, 1 PP 1-15.
- Vance McLaughlin, (2006) The Postcard Killer: The True Story of J. Frank Hickey, Running Press.
- Schlesinger, Louis (2009). "Psychological profiling: Investigative implications from crime scene analysis". The Journal of Psychiatry & Law 37 (1): 73–84.
- Hitler's health problems, including Parkinson's disease, are now well known.
- Gladwell, Malcolm (2007-11-12). "Dangerous Minds: Criminal profiling made easy.". The New Yorker. Retrieved 2008-01-01. "James Brussel didn’t really see the Mad Bomber in that pile of pictures and photostats, then. That was an illusion. As the literary scholar Donald Foster pointed out in his 2000 book "Author Unknown," Brussel cleaned up his predictions for his memoirs. He actually told the police to look for the bomber in White Plains, sending the N.Y.P.D.’s bomb unit on a wild goose chase in Westchester County, sifting through local records. Brussel also told the police to look for a man with a facial scar, which Metesky didn’t have. He told them to look for a man with a night job, and Metesky had been largely unemployed since leaving Con Edison in 1931."
- Casebook of a Crime Psychiatrist, James A. Brussel, Bernard Geis Associates (1968), Classic, ISBN 0-583-11804-6
- "Organized crimes are premeditated and carefully planned. These characteristics suggest that the perpetrator may display psychopathic tendencies, because this type of person remains in touch with reality, under stress. Little evidence is found at the scenes of this type of offender, they are antisocial but understand right from wrong, but have a shallow affect; thus not showing remorse. Disorganized crimes are unplanned, impulsive acts of violence. This individual uses weapons available at the scene, like blunt force objects for example. They leave many forms of evidence, like fingerprints and blood. Being out of touch with reality and social norms, these offenders are clinically psychotic." Criminal Profiling: An Introduction to Behavioral Evidence Analysis, Brent Turvey, San Diego: Academic Press (1999).
- Canter, D. (2004). Offender Profiling and Investigative Psychology. Journal of Investigative Psychology and Offender Profiling, 1 PP 1-15.
- Criminal Profiling: An Introduction to Behavioral Evidence Analysis, Brent Turvey, San Diego: Academic Press (1999).
- "The Washington DC-area sniper, who is most likely a white male in his thirties, may have recently been fired from or resigned from his job under contentious circumstances." Immelman, Aubrey (2002) "Provisional Psychological Profile of the October 2002 Washington, D.C.-Area Sniper," URL retrieved 26 April 2011.
- Perri, Frank S. and Lichtenwald, Terrance G. (2009). "When Worlds Collide: Criminal Investigative Analysis, Forensic Psychology and the Timothy Masters Case",Forensic Examiner, 18:2, NCJ # 226972.
- Malcolm Gladwell (2007-11-12). "Dept. of Criminology: "Dangerous Minds: Criminal profiling made easy."". The New Yorker (New York). Retrieved 2008-01-04.
- Swiss scientific research site on criminal profiling
- University of Liverpool Forensic Psychology - with articles
- History of Criminal Profiling - with links to other sites
- Offender Profiling: An Introduction to the Sociopsychological Analysis of Violent Crime - PDF available
- Dangerous Minds: Criminal profiling made easy, by Malcolm Gladwell