offender profiling - the bottom-up approach

Question 1

the bottom-up approach

Answer 1

• aim is to generate picture of offender, including their likely characteristics, routine behaviour and social behaviour, through systematic analysis of evidence at the crime scene
• unlike the US top-down approach, an investigation using the British bottom-up model does not begin with fixed typologies
• the profile is ‘data-driven’ and emerges as investigator engages in deeper and more rigorous scrutiny of the details of the offence
• bottom-up profiling is more grounded in psychological theory than the top-down approach

Question 2

investigative psychology

Answer 2

• discipline of investigative psychology is attempt to apply statistical procedures, alongside psychological theory, to the analysis of crime scene evidence
• aim in relation to offender profiling is to establish patterns of behaviour that are likely to occur across crime scenes, in order to develop statistical database which acts as a baseline for comparison
• specific details of an offence can then be matched against the database reveal important details abut the offender, their personal history, family background etc.
• may also determine whether a series of offences are linked or likely to have been committed by the same person
• concept of interpersonal coherence (the way an offender behaves at the scene may reflect their behaviour in more everyday situations)
• significance of time and place is also a key variable, may indicate where the offender is living
• forensic awareness describes individuals who have been the subject of police interrogation before, their behaviour may denote how mindful they are of covering their tracks

Question 3

geographical profiling

Answer 3

• uses information about location of linked crime scenes to make inferences about likely home or operational base of an offender (known as crime mapping, based on spatial consistency - people commit crimes within a limited location)
• can be used in conjunction with psychological theory to create hypotheses about how the offender is thinking
• assumption is that serial offenders restrict their work to geographical areas they are familiar with, so understanding the spatial pattern of their behaviour provides investigators with a centre of gravity which is likely to include offender’s base (often in middle of spatial pattern)
• crime locations inputted into database to statistically predict where the offender might live / work
• this is basis of Canter’s circle theory, as pattern of offending forms a circle around the offender’s home base
• distribution of offences leads us to describe an offender in one of two ways -
  1) the marauder - who operates in close proximity to their home base
  2) the commuter - who is likely to have travelled a distance away from their usual residence
• spatial decision-making can offer investigative team important insight into nature of offence (ie. whether it was planned or opportunistic), as well as revealing other important factors about offender such as their mode of transport or approximate age

Question 4

evaluation strength - evidence for investigative psychology

Answer 4

• Canter and Heritage conducted analysis of 66 sexual assault cases, examined data using smallest space analysis
• several behaviours identified as common in different samples of behaviour, such as the use of impersonal language
• each individual displayed characteristic pattern of such behaviours, this helps to establish whether two or more offences were committed by the same person (case linkage)
• supports one of the basic principles of investigative psychology that people are consistent in their behaviour

Question 5

evaluation limitation - counterpoint to evidence for investigative psychology

Answer 5

• case linkage depends on database, this will only consist of historical crimes that have been solved
• the fact they were solved may be because it was relatively straightforward to link the crimes together in the first place, making this a circular argument
• suggests that investigative psychology may tell us little about crimes that have few links between them and therefore remain unsolved

Question 6

evaluation strength - evidence for geographical profiling

Answer 6

• Lundrigan and Canter collated info from 120 murder cases involving serial killers
• smallest space analysis revealed spatial consistency in behaviour of killers, organised vs disorganised
• location of each body disposal site created centre of gravity presumably because, when offenders start from home base, they may go in a different direction each time they dispose of body, but in the end all these sites create a circular effect around home base
• offender’s base was invariably located at the centre of the pattern, effect was more noticeable for marauders
• supports view that geographical info can be used to identify an offender

Question 7

evaluation limitation - geographical information insufficient ⭐️

Answer 7

• success of geographical profiling may be reliant on quality of data that police can provide
• recording of crime is not always accurate, can vary between police forces and an estimated 75% of crimes are not even reported to police
• calls into question the utility of an approach that relies on accuracy of geographical data
• critics also claim that other factors are just as important in creating a profile, such as timing of an offence
• suggests that geographical information alone may not always lead to successful capture of an offender

Question 8

evaluation strength - support from John Duffy (railway rapist) ⭐️

Answer 8

• appeared to be a marauder, crimes based in central london, most crimes occurred at train stations
• used geographical profiling to identify that he lived in Kilburn, this was true
• many other features of his profile were correct, such as having marriage problems
• bottom-up profiling / geographical profiling allowed police to catch John Duffy and sentence him to life in prison
• increases validity of bottom-up approach, supports use of geographical profiling and interpersonal coherence

Question 9

evaluation limitation - mixed results

Answer 9

• Copson analysed bottom-up profiling being used in real life
• in only 3% of cases did the profile lead to accurate identification of the offender
• even times where a false profile was created (eg. Rachel Nickell)
• decreases validity of approach