offender profiling:bottom up approach Flashcards
(6 cards)
Intro
The aim of the bottom-up approach is to generate a picture of the offender - their likely characteristics, routine behaviour and social background - through systematic analysis of evidence at the crime scene. Unlike the US top-down approach, an investigation that is using the British bottom-up model does not begin with fixed typologies. Instead, the profile is data-driven’ and emerges as the investigator engages in deeper and more rigorous scrutiny of the details of the offence. Bottom-up profiling is also much more grounded in psychological theory than the top-down approach, as we shall see.
Investigative psychology
The discipline of investigative psychology is an attempt to apply statistical procedures, alongside psychological theory, to the analysis of crime scene evidence. The aim, in relation to offender profiling, is to establish patterns of behaviour that are likely to occur - or coexist - across crime scenes. This is in order to develop a statistical database which then acts as a baseline for comparison. Specific details of an offence, or related offences, can then be matched against this database to reveal important details about the offender, their personal history, family background, etc. This may also determine whether a series of offences are linked in that they are likely to have been committed by the same person.
Central to the approach is the concept of interpersonal coherence - that the way an offender behaves at the scene, including how they ‘interact’ with the victim, may reflect their behaviour in more everyday situations. For instance, whilst some rapists want to maintain maximum control and humiliate their victims, others are more apologetic (Dwyer 2001). This might tell police something about how the offender relates to women more generally.
The significance of time and place is also a key variable and, as in geographical profiling below, may indicate where the offender is living.
Finally, forensic awareness describes those individuals who have been the subject of police interrogation before, their behaviour may denote how mindful they are of ‘covering their tracks.
geographical profiling
Geographical profiling uses information about the location of linked crime scenes to make inferences about the likely home or operational base of an offender - known as crime mapping and based on the principle of spatial consistency (that people commit crimes within a limited geographical space). It can be used in conjunction with psychological theory (such as that informed by investigative psychology above) to create hypotheses about how the offender is thinking as well as their modus operandi.
The assumption is that serial offenders will restrict their work’ to geographical areas they are familiar with, and so understanding the spatial pattern of their behaviour provides investigators with a ‘centre of gravity’ which is likely to include the offender’s base (often in the middle of the spatial pattern).
This is the basis of Canter’s circle theory (Canter and Larkin 1993) because the pattern of offending forms a circle around the offender’s home base. In addition the distribution of offences leads us to describe an offender in
one of two ways:
• The marauder - who operates in close proximity to their home base.
• The commuter - who is likely to have travelled a distance away from their usual residence.
Such spatial decision-making can offer the investigative team important insight into the nature of the offence, i.e. whether it was planned or opportunistic, as well as revealing other important factors about the offender, such as their ‘mental maps’, mode of transport, employment status, approximate age, etc.
Strength-evidence for investigative psychology
One strength of investigative psychology is that evidence supports its use.
David Canter and Rupert Heritage (1990) conducted an analysis of 66 sexual assault cases. The data was examined using smallest space analysis (see previous spread). Several behaviours were identified as common in different samples of behaviour, such as the use of impersonal language and lack of reaction to the victim. Each individual displayed a characteristic pattern of such behaviours and this can help establish whether two or more offences were committed by the same person (referred to as’case linkage).
This supports one of the basic principles of investigative psychology (and the bottom-up approach) that people are consistent in their behaviour.
Counterpoint However, case linkage depends on the database and this will only consist of historical crimes that have been solved. The fact that they were solved may be because it was relatively straightforward to link these crimes together in the first place. Which makes this a circular argument.
This suggests that investigative psychology may tell us little about crimes that have few links between them and therefore remain unsolved.
Strength-evidence for geographical profiling
Another strength is evidence to support geographical profiling.
Samantha Lundrigan and David Canter (2001) collated information from 120 murder cases involving serial killers in the US. Smallest space analysis revealed spatial consistency in the behaviour of the killers. The location of each body disposal site created a centre of gravity’ presumably because, when offenders start from their home base they may go in a different direction each time they dispose of a body, but in the end all these different sites create a circular effect around the home base. The offender’s base was invariably located in the centre of the pattern. The effect was more noticeable for offenders who travelled short distances (marauders).
This supports the view that geographical information can be used to
identify an offender.
limitation-geographical information is insufficient
One limitation is that geographical profiling may not be sufficient on its own.
As with investigative psychology, the success of geographical profiling may be reliant on the quality of data that the police can provide. Unfortunately, recording of crime is not always accurate, can vary between police forces and an estimated 75% of crimes are not even reported to police in the first place (criminologists often refer to this as the dark figure of crime). This calls into question the utility of an approach that relies on the accuracy of geographical data. Even if this information is correct, critics claim that other factors are just as important in creating a profile, such as the timing of the offence and the age and experience of the offender (Ainsworth 2001).
This suggests that geographical information alone may not always lead to the successful capture of an offender.
