The bottom-up approach Flashcards
aim of bottom up approach
to generate a picture of the offender through systematic analysis of evidence at the crime scene. The profile is data-driven.
Investigative psychology
Apply statistical procedures to the analysis of crime scene evidence. Aim is to establish patterns of behaviour that are likely to occur across crime scenes. This is done in order to develop a statistical database which then acts as a baseline for comparison. Can determine whether a series of offences are likely to have been committed by one offender.
Central to the approach is interpersonal coherence – way an offender behaves at crime scene gives clues as to how they behave in real life. Significance of time and place is a key variable – may indicate where offender lives. Forensic awareness also describes those individuals who have been the subject of police interrogation before.
geographical profiling
Uses information about location of linked crime scenes to make inferences about likely home of offender, known as crime mapping. Based on the principle of spatial consistency that people commit crimes within a limited geographical space. The assumption is that serial offenders will restrict their work to geographical areas they are familiar with. This provides a ‘centre of gravity’ which is likely to include the offenders home base.
Centre of gravity is basis of Canter’s circle theory because the pattern of offending forms a circle around offenders home base. Distribution of offences leads to describing an offender as The Marauder or The Commuter.
The marauder – operates in close proximity to home base
The commuter – likely to have travelled a distance away from their usual residence
Evaluation of bottom-up profiling (brief)
strength - evidence for investigative (canter and heritage)
strength - evidence for geographical (lundrigan and canter)
weakness - geographical insufficient on its own
strength of bottom-up profiling
😊 evidence supports the use of investigative psychology. Canter and Heritage (1990) conducted an analysis of 66 sexual assault cases. The data was examined using smallest-space analysis and several behaviours were identified as common such as use of impersonal langauge. Each individual displayed a characteristic pattern of such behaviour and this can help establish whether two or more offences were committed by the same person. This supports one of the basic principles of investigative psychology that people are consistent in their behaviour. However, case linkage depends on the database and this will only consist of historical crimes that have been solved. This suggests that investigative psychology may tell us little about crimes that have few links between them and therefore remain unsolved.
😊 evidence supports geographical profiling. Lundrigan and Canter (2001) collated information from 120 murder cases involving serial killers in the US. Smallest space analysis revealed spatial consistency in the behaviours of the killers. The location of each body disposal site created a ‘centre of gravity’. The offenders 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 profiling can be used to identify an offender.
weakness of bottom-up profiling
🙁 geographical profiling may be insufficient on its own. The success of geographical profiling may be reliant on the quality of data the police can provide. Recording of crime is not always accurate and can vary between police forces. An estimated 75% of crimes aren’t even reported to the police in the first place. 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 other factors are just as important in creating a profile, such as timing of the offence and the age and experience of the offender (Ainsworth 2001). This suggests that geographical profiling may be more useful when used in conjunction with other techniques.
