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The methods employed by David Canter are similar to those employed by the FBI
in that they are both largely statistical in nature. The main difference is that
Canter is continually updating his database of offender populations on which to
base his theories [Reference 11]. By statistical, I mean that known offender
populations are studied, broad offender groups (known as typologies) are
defined, and the crimes of an unknown offender compared to this group. This
subsequently produces a list of characteristics likely to be possessed by
the unknown offender by virtue of their similarity to the comparison (or known)
offender group.
The origins of Investigative Psychology can be traced back to
1985, when David Canter was called to Scotland Yard to discuss the possibility
of integrating investigation techniques with psychological concepts [Reference
12]. Canter was unsure whether this could be accomplished, but decided to apply
some of the methods of environmental psychology to criminal investigation, most
notably the Railway Rapist (John Duffy).
Canter developed a University program revolving around the
methods he had adapted to criminal investigation and started teaching his
approach to profiling while at the University of Surrey. He later moved to the
University of Liverpool where he offers an Investigative Psychology program to
students from around the world. Canter’s research focuses primarily on which
of the established psychological principles can be adapted to, or used for, the
development of profiles in the investigation of crime [Reference 11].
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.
Interpersonal 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 [Reference 11]. It is assumed
that offenders will deal with their victims in similar ways that they deal with
people in their 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, and Canter cites anecdotal evidence in support of this [Reference 13].
One such example would be Ted Bundy, whose victim selection was believed to
represent his ex-girlfriend.
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 the way
in which the offender views their surroundings, and may also be heavily
influenced by how they view their own schedule. The time of an attack, for
instance, may provide insight into their work or play schedule, and thus give
clues about their personal life.
Criminal Characteristics: Used to allow researchers to
develop subsystems for the classification of offender groups, which may be used
to provide characteristics to investigators that are likely to be possessed by
the perpetrator in the current crime. The FBI’s classification of the offender
as ‘organised’ or disorganised’ is one such system used in identifying
criminal characteristics, though Canter himself sees that this system is of
little use considering there is so much overlap between the two classifications
[Reference 7 and 14].
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
closely related to the last concept, forensic awareness.
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 a 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 might indicate this is not his first sexual assault. This
information may be given to police, who take the information and compare it to
known offenders, the suspects already generated, or by reducing the known
suspect pool by excluding those with no prior offences in either of the two
areas above.
Canter has also developed a model of offender behaviour known
as the circle theory, which developed directly from environmental psychology.
Two models of 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 their crimes, whereas the commuter 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.
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