Bottom-Up Offender Profiling

• what is the bottom-up approach?

  • aim is to generate a picture of the offender through systematic analysis of evidence at the crime scene
  • doesn't have fixed topologies/categories
  • done through database analysis and is more grounded in psychological theory
  • aims to create hypotheses about offenders modus operandi
  • includes - geographical profiling, investigative psychology, small space analysis, interpersonal coherence
• what is investigative psychology?

  • matches details from crime scene with statistical analysis of typical offender behaviour patterns, based on psychological theory
  • includes interpersonal coherence
• what is geographical profiling?

  • uses locations of linked crime scenes to make inferences about operational base and identity of offender
  • use of crime mapping which is based on spatial consistency, assumes offenders will restrict 'work' to familiar areas, providing a 'centre of gravity'
  • includes canter's circle theory, small space analysis and space and time
• what is small space analysis?

  the output from the programmes used to generate a profile based on the evidence of a crime scene, closer to the middle the factors are when you rate them, the more likely they are to have a positive correlation with each other
• what is Canter's Circle theory?

  • helps to establish the likely location of the home of an offender using the distribution of offences
  • two types - commuter model (offences away from home) or marauders model (offences close to home)
  • helps to gain insight into nature of offence - planned or opportunistic
  • can help to learn the mode of transport, employment status, age etc
• describe the case study of John Duffy (Railway Rapist)

  • psychologist Canter helped the police in the capture
  • Duffy carried out 24 sexual attacks on women and 3 murders near railway stations in North London
  • Canter analysed geographical information from crime scenes and details of past attacks
  • from this he drew up a profile of Duffy which was surprisingly accurate and led to his arrest and conviction
• describe the case study of Rachel Nickell

  • 1992, 21 year-old Rachel Nickell was stabbed 47 times and sexually assaulted in a frenzied attack on Wimbledon Common
  • her 2 year-old son was the only witness
  • offender profiler Paul Britton was enlisted to help
  • Colin Stag, local man who often walked his dog on the common fitted the profile
  • Britton, with police instigated a 'honey trap' - undercover police - woman pursued Stagg to try to get him to confess
  • 2008, following forensic evidence Robert Napper was convicted, originally ruled out for being too tall
• is interpersonal coherence?

  analysing offender behaviour to help the understand offender behaviour in their day-to-day life e.g. way offender may communicate with their victim can indicate attitude they display in real life
• what is space and time?

  central principle of geographical profiling - time and location of the crime will communicate something about the offender's own residence/employments