Bottom-up Approach

• What is the bottom-up approach?

  When profilers work up from evidence found at the crime scene to develop hypotheses about likely characteristics of the offender by making inferences from systematic analysis at the crime.
• What are the two types of bottom-up profiling?

  Investigative psychology and Geographical profiling
• What is investigative profiling?

  Matches details from the crime scene with statistical analysis of typical offender behaviour patterns based on psychological theory.

  Central to the approach is the concept of 'interpersonal coherence' - the was an offender behaves at the crime scene and how they interact with the victim
• What is the supporting evidence for investigative psychology?

  • Canter and Heritage
  • Conducted a content analysis of 66 sexual assault cases
  • Data was examined using smallest space analysis
  • FINDINGS
  • Common characteristics identified: impersonal language and lack of reaction to the victim.
  • This supports the usefulness of IP as it shows how statistical techniques can be applied.
• What is geographical profiling?

  A form of bottom-up profiling based on principle of spatial consistency: that an offender's operational base and possible future offences are revealed by the geographical location of their previous crimes.
• What is the Circle theory Canter and Larkin proposed?

  Proposes two models of offender behaviour:

  • Marauder - who operates in close proximity to their home base.
  • Commuter - who is likely to have travelled a distance away from their usual residence.
• What is the research evidence for geographical profiling?

  • Lundrigan and Canter
  • Collated from 120 murder cases involving serial killers in the USA.
  • Used smallest space analysis which revealed spatial consistency in the behaviour of killers.
  • FINDINGS:
  • Location of each body disposal site was in different sites, creating a 'centre of gravity' around the offender's base.
  • The effect is more noticeable in the marauder than the commuter
• What was the case study supporting bottom-up profiling?

  • John Duffy
  • John Duffy carried out 24 sexual attacks and 3 murders on women near railway stations.
  • Canter analysed geographical information from the crime scenes and combined this with details of similar attacks in the past supplied by police.
  • In doing so Canter was able to draw up a profile which was surprisingly accurate and led to his eventual arrest and conviction.