- Created by: Faye
- Created on: 27-02-10 15:14
What is offender Profiling?
- Providing description of offender based on analysis of crime scene,victim and other evidence - Tends to be used with serious crime especially serial offenders.
The goals of profiling(Holmes & Holmes, 1996)
1. Social and Psychological assessment of offender- basic info e.g. personality,race,employment,religion, marital status, level of education 2. Psychological evaluation of possessions likely to belong to offender. 3.Suggesting strategies to use when interviewing suspects.
1. The American 'Top down' approach
-Starts with classification system at the top and uses this to prepare a profile to suit the evidence
-Pre-prepared profile used to interpret evidence (theory driven)
-Based on interviews with criminals
2. The British 'bottom up' approach
-stats with pieces of evidence then makes links between them e.g. location,time,forensic,awarness to draw up profile.
-Evidence used to prepare profile (data driven)
-Behaviour of criminal used as data source
The American Top- Down Appoach
-Developed by FbI
-Interviewed 36 convicted sexually orientated male murders (e.g. Ted Bundy. Charles Manson) and collected detalied informationabout crimes from members of behavioural science unit.
-From this analysis the researchers identified two types of offender (a typology)
1. An Organised Offender
Leads an ordered life and kills after some sort of critical life event. Their actions are premeditated and planned, they are likely to bring weapons and restrain to the scene. They are likely to be of average to high intelligence and employed.
2. A Disorganised Offender
Is more likley to have committed the crime in a moment of passion. There will be no evidence of premeditation and they are more likely to leave evidence such as blood, semen,murder weapons ect. behind. This type of offender is though to be less socially competent and more likely to be unemployed
Evidence of planning, Victim targeted, Victim personalised, Controlled conversation, Crime Scene reflets control, Victim submissive, Use of restraints, Aggressive acts prior to death, Body Hidden,Weapon and evidence absent, Above avergae IQ, Socially and sexually competent,Usually living with partner,Experiencing anger/depression at the time of the attack, Follow media coverage of the attack.
Spontaneous offence, Victim or location known, Victim depersonalised, Minimal conversation,Crime scenerandom or sloppy,Sudden voice of victim,Minimal use of restraints,sexual acts after death,Body left in view,Weapon and evidence often present,Lives alone-near to crime scene. Sexually and socially inadequate, Experiences serve forms of mental illness, Physically or sexually abused in childhood, Frightened and confused at the time of attack.
This approach uses this categorisation to interpret the crime scene.
The British Bottom up Approach
The British Bottom Up Approach- The leading British profiler is David Canter
David Canter's approach looks for ways in which the crime might mirror the behaviour of the offender in everyday life. He looks at the behaviour of the criminal when commiting the crime and then infers how the criminal may act in every day life.
His approach is based on the idea that offenders, like all people, act consistently over time and in diffrent situations. This is known as the criminal consistency hypothesis.
Therefore, the way in which a crime is committed will reflect the everyday behaviour and traits of the offender
The consistency hypothesis has been applied to two areas:
-Interpersonal consistency(Interations between the victim and the offender)
- Spatical consistency (The geographical area in which the offender commits thier crimes)
Five Applications of Canter's work
The application of canter's work is based on five aspects of the interaction between the victim and the offender, known as the five-factor model. This model includes interpersonal coherence, significance of time and place, criminal characteristics, criminal career, and forensic awareness.
1. Interoersonal Coherence: Refers to whether a variation in criminal activity will relate to variations in the way in which the offender deals with other people in non-criminal situations. It is assumed that offenders will deal with thier victims in similar ways that they deal with people in thier day-to-day lives. It is further assumed that victims may represent significant people in the life of the offender outside of the criminal event. One such example would be Ted Bundy, whose victim selection was believed to represent his ex girlfriend.
2.The significance of time and place: May provide the analyst with information about offender mobility, and therefore guide inferences about likely residential location. As the time and place of the event is largely chosen by the offender, this is seen to be important as it may represent they way in which the offender views their surroundings, and may also be heavily influenced by how they view thier surroundings, and time of an attack, for instance, may provide insight into thier work or play schedule, and thus gives clues about thier personal life.
Five Applications of Canter's work
3.Criminal Characteristics: Used to allow researchers to develop subsytems for the classification of offender groups. Which may be used to provide characteristics to investigators that are likely to be possessed by the prepetrator in the current crime. The FBI's classification of the offenders as 'Organised' or Disorganised' is one such system used in identifying criminal characteristics.
4.Criminal Career:Simply refers to an assessment that is made to determine whether the offender may have engaged in criminal activity in the past, and what kind of activity this is most likely to have been. it is closley related to the last concept, forensic awareness.
5.Forensic Awareness:Is any evidence that an offender has knowledge of, or may be privy to, police techniques and procedures relating to evidence collection. It may include, but is not limited to, the wearing of gloves,the use of condom, or the removal of any items contaminated with the offender's bodily fluids. An assessment of the criminal career may indicate the offender's skill in getting him onto the premises, which might be suggestive of previous offences in burglary, while the way in which he bathes the victim after the sexual assault may indicate this is not his first sexual assault.
Five Applications of Canter's work
Canter has also developed a model of offender behaviour known as the circle theory which was developed directly from environmental psychology. Two models offender behaviour known as the "marauder" and "commuter" hypothesis were developed from the circle theory. The marauder model assumes that an offender will "strike out" from their home base in the commission of thier crimes, wherreas the computer model assumes that an offender will travel a distance from their home base before engaging in criminal activity. A basic graphical model of this hypothesis is shown in the diagram below.
Canter- John Duffy- The Railway ******
Between 1975 and 1986 23 woman were ***** between aged 15 and 32 at railway stations in and around London. Canter became intrested in the case after reading reports in the evening standard. In the early 1980s 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 ****** might live. He categorised perpetrators as 'marauders' or 'commuters'. Depending on whether they strike from within their base 'marauders' or travel away from home 'commuters'
Residence: Has lived in the areas circumscribed by the first three cases since 1983 -Probably lived in that area at the time of the arrest -Probably lived with a wife or girlfriend, possibly with no children.
Age etc. Mid to late twenties Light hair About 5 feet 9 inches Righthanded
Probably semi skilled or involving weeked or casual labour from july 1984 onwards
His job most likely does not bring him into contact with the public
Keeps himself to himself, but has one or two close men friends and probably very little contact with woman, especially in the work siuation,
Has knowledge of the railway system, along which the attacks happen.
The variety of his sexual actions suggests considerable sexual experience.
Was probably arrested some time between 24 october 1982 and january 1984 and this may have had nothing to do with ****, but having been agressive under the influence of drugs or alcohol.
The profile represents the first attempt to use behavioural charecteristics to search for a criminal instead of purley forensic evidence from the crime scene.
In November 200 John Duffy who was serving life for **** and murder of several women.confessed that he was responsible for many more and that he committed some with accomplice David Mulcahy. He was the railway ******.
John Duffy had been interviewed by the police for an unrelated offence, a 'domestic' against his ex-wife. He was one of 2000 suspects connected to the crime by their blood groups. He lived in Kilburn North London, had worked on the railways as a carpenter and was the right age. The profile did fit on these criterion.
However, Duffy was a lot shorter that victims remembered and many had described him as having black or even ginger hair, but police, suggested that the 'weapon effect' may have played apart as he threatened victim's with a knife.