So Pinizotto and Finkel's research showed clearly that FBI trained profilers are not
consistently better at identifying the likely characteristics of an offender. And this ambiguity
as to the superiority of FBI trained profilers comes through in all the published accounts.
On some dimensions some profilers out-perform relevant others,
and on other dimensions they don't.
So what alternative approaches exist that use the crime scene to infer something of
the characteristics of the offender? Probably the most famous alternative approach is Investigative Psychology
that emerged from David Canter's work. Now in terms of using the crime scene
to tell us something about the offender, the aim of Investigative Psychology is much the
same as that of the FBI's approach. Essentially you want to be able to tell the investigating
officers something about the characteristics of an offender from their actions while committing
the crime. This will then allow investigators to narrow down their search of suspects.
However in contrast to the FBI's approach, Investigative Psychology attempts to identify
these characteristics by analysing behaviour in a way that is independent of the psychological
mechanisms that underpin it. That is, Investigative Psychology is not focused on identifying 'why'
the offender commits the crime. Instead, Investigative Psychology simply infers the characteristics
of the offender from the known actions taken by the offender during the crime.
With this approach, it is possible to statistically analyse larger data sets to break down crime
scenes into their component parts and then relate these components to distinct aspects
of the offender. These analyses are then submitted for publication in peer-reviewed journals
where other researchers critically evaluate whether the analysis has been conducted according
to the appropriate research practices.
Unlike the FBI's case by case approach, analysis of large data sets in this way allows
more certainty in determining how often particular types of behaviour are seen in particular
crimes. A good example of this approach is seen in an early analysis conducted by Salfati
& Canter that was published in 1999.
Salfati and Canter looked at 82 British cases of single perpetrator-single victim homicide
crime scenes that had been solved. They were interested to see whether there would be a
thematic structure to the actions that occurred at these crime scenes.
So they coded the information in the police homicide files for the presence or absence
of a range of variables, which reflected:
* actions by the offender on the victim, * descriptions of behaviour carried out by
the offender at the crime scene
* characteristics of the offender and
* characteristics of the victim.
Now variables that occurred in more than 90% of cases or in less than 10% of cases were
excluded as they were seen to be either too common or too rare to help the classification.
Salfati and Canter then analysed this data to detect the co-occurrence of each variable
with each other variable. And this analysis allowed them to produce a visual representation
of factors that frequently co-occurred and those which were very unlikely to co-occur
in this type of crime.
So for example, Salfati and Canter found that in these homicide cases, it was unusual to
find a body facing up where property of value had been taken from the victim or the crime
scene. Now through this analysis Salfati and Canter identified three crime scene themes
which reflect the role of the aggression in the offence.
The first of these is expressive (impulsive) where the underlying aim of the aggression
seems to be to hurt the victim. Instrumental (opportunistic) and instrumental (cognitive) is where the
murder is a byproduct of other more dominant motives such as the desire for objects.
Now of the 82 cases included in this analysis, 53 cases could be classified as showing a
dominant impulsive, opportunistic or cognitive crime scene theme. And of these 53 cases,
21 followed an impulsive theme of homicide crime scene behaviour. So, an expressive impulsive
crime scene comprised multiple stab wounds across the victim's body, many other types
of wounds, bringing a weapon to the scene and using a weapon from the scene in amongst
other behaviours. Contrast this with an instrumental cognitive crime scene where, for example,
offenders attempted to hide their crime: either by committing it outside or disposing of the
body outside, and by removing evidence from the crime scene.
Now as this analysis used solved cases, offender characteristics were known, so it was possible
to see which offender characteristics co-occurred with which crime scene behaviours. So, for
example, someone whose crime scene was classified as expressive impulsive was statistically
likely to have committed prior violent or sexual offences, prior damage to property
offences and/or to have been previously married. Those classified as having instrumental cognitive
crime scenes were statistically more likely to have served in the armed forces or had
a prior prison sentence.
So you can see how, as long as the perpetrator in any given case doesn't deviate from the
'typical' behaviour determined by the analysis of data from this sample, this information
would allow for a more focused targeting of suspects. That is, if you have an expressive
instrumental crime scene then, with all other things being equal, you should start your
further investigations with those suspects who have prior charges for offences that suggest
conflict with or against other people.
The other notable aspect of the analysis of Salfati and Canter is that the interactional
behaviour of offenders while offending does not seem to deviate too far from their interactional
behaviour or style when not offending. Now David Cantor, the chief proponent of Investigative
Psychology, suggests that the way in which people interact with one another in their
everyday lives is so well rehearsed and ingrained that it influences all their interactions
with others, including the way that they interact with their victim while they are offending. That is
there is coherence in their personal interactions.
And interpersonal coherence is one of the factors in Canter's five-factor model for
interpreting a crime scene, which aims to tell the investigators about the offender's
past and present experiences in life. The second factor in this model is time and space
considerations in the choice of where the crime or crimes took place. Crime scenes are
rarely random. Offenders select the time and location of their offending for a reason.
So investigators may be able to infer something about the offender based on their choices
about when and where to offend.
For example, Cantor proposed that if an offender is engaging in an offence where he needs to
feel in control, then the offender is likely to do this in a place that is familiar to
him, perhaps closer to his base where he feels more comfortable, knowledgeable and in control
of what goes on.
Behaviour engaged in or not engaged in at the crime scene can also tell you valuable
information about the offender's background. This may be as simple as an indication of
the likely level of intelligence of the offender, but it may be more detailed. For example,
an offender who uses a knife in a very specific or specialized way, might have had training
in their occupation to use the knife that particular way.
This behaviour will also give you insight into the offender's forensic awareness,
and this is the third factor in Canter's five-factor model. Imagine, for example, that
at a crime scene it was clear that the offender had made little effort to cover up or remove
forensic evidence. This may suggest that they do not have much experience on offending because
they are not trying to evade forensic evidence collection techniques. So this offender may
have few or no prior convictions.
Forensic awareness is closely related to the fourth factor of criminal career. This is
the idea that offenders will behave relatively consistently in committing their crimes, so
any previous offences committed by this offender will resemble the current offence. Criminal
career also covers the idea that deviations or changes away from the pattern of previous
offending may be in response to something that happened while this person was attempting
to commit their crime. For example, an offender who has never drugged their victim before
might drug their victims in the future because a victim struggled in response to the attack.
The final factor is criminal characteristics. This is the idea that you can use characteristics
of the offence to match it to similar types of crime. Now an obvious question here is how
does this five factor approach help us figure out what kind of person might have committed
the crime? Well once you have considered the crime scene in light of the five-factor model
of offender experiences, you can then make inferences about the characteristics the offender
might have. So this might include inferences about the offender's residential location,
their domestic or their social characteristics, their personal characteristics and their occupation
or education history.
This means that once investigators have gathered information about the likely characteristics
and experiences of the offender they will have a description of the sort of individual
who may have committed the crime. This can help focus the investigation of the offence.
Now at this point it may sound like Investigative Psychology is very similar to the FBI's
Criminal Investigative Analysis approach. Both seem to generate profiles of 'typical'
offenders, which as we saw from the analysis of Pinizotto and Finkel causes problems when
your offender is in the minority that is not typical. A key question then is how is Investigative
Psychology different?
Well while both Criminal Investigative Analysis and Investigative Psychology both involve
the investigator making inferences about the offender's likely characteristics on the
basis of the crime scene, the emphasis in each type of profile is distinct. Profiles
generated by Criminal Investigative Analysis tend to focus on an offender's characteristics
and their likely motivation. In contrast profiles created by Investigative Psychology tend to
focus on the offenders characteristics and information about the offender's likely
location. Typically also, Canter and colleagues research uses larger sample sizes than the
FBI and subjects the research underpinning their inferences to peer review.
So Canter and Alison (2000, P1) talk of an analysis of criminal actions from an objective,
often statistical viewpoint rather than one based on personal intuition and clinical experience.
However, it is worth noting that this reliance on statistical methods might introduce its
own problems in that at best these kinds of statistical analyses can only show associations
between crime scene actions and offender characteristics. And these associations will never be perfect,
meaning that there is always the possibility that your particular offender is an exception
- a statistical outlier if you like - to the general pattern of association seen in
that type of case
However, investigative psychology does suggest a more systematic approach to working out
the characteristics of the offender. So while David Canter is most well known for profiling
John Duffy, the so-called railway rapist, since then Investigative Psychology has grown
as a subdiscipline. Now, those working in Investigative Psychology are interested in
patterns of criminal behaviour more broadly, and they can help investigators deal with
a range of crimes.