offender profiling - bottom-up

• Used in Britain – developed by Canter

  The bottom-up approach is data-driven and  aims to create a picture of the offender (characteristics, routine, behaviour, background) through analysis of the crime scene. Unlike the top-down approach, it does not have fixed typologies.

  Uses:

  • Investigative psychology
  • Geographical profiling
• investigative psychology -

  • Statistical procedures detect patterns of behaviour that are likely to occur across crime scenes
  • features of an offence can be matched against a database to suggest potential details about the offender
  • Interpersonal coherence – The way an offender behaves while committing a crime e.g. how they interact with victim may reflect their every day behaviour.
• geographical profiling -

  • Crime scene locations are used to infer the likely home/workplace of the offender (crime mapping)
  • Assumes serial offenders restrict their crime to areas they are familiar with: The marauder – offends close to home base and The commuter – likely to have travelled to commit the offence
  • Locations of offending are likely to form a circle around offenders home base and can provide info about the offender (plan or opportunity, transport, employment status)
• strength -

  Content analysis of 66 sexual assault cases found common characteristics in most cases e.g. impersonal language, lack of reaction to victim. This can help us to understand how offenders behaviour can change over offences/determine whether 1 person committed 2 crimes.

  Supports the usefulness of investigative psychology as it shows how statistical techniques can be applied to accurately profile offenders.
• strength -

  Research on 120 murder cases involving serial killers revealed spatial consistency in the behaviour of offenders and this was more noticeable for offenders who travelled short distances (marauders)

  Supports Canters claim that spatial information is a key factor in determining the base of an offender
• strength -

  Geographical profiling helps to locate offenders of many different crimes e.g. burglary/theft/murder etc.

  The bottom-up approach is more valuable than the top-down approach as an investigative technique as it can be applied to many different types of crime.
• weakness -

  Copson surveyed 48 police forces and found the advice provided by the profiler was useful in 83% of cases but only led to the accurate identification of the offender in 3%.

  This questions the effectiveness of the bottom-up approach in actually identifying offenders.