bottom up offender profiling

• investigative psychology

  • developed by Canter
  • proposed profiling should be based on psych theory and research
• interpersonal coherence

  • people are consistent in their behaviour, so there will be links with how people behave in everyday life
  • but may change over time
• forensic awareness

  • past experience
  • eg. rapists who conceal fingerprints often had previous burglary conviction
• smallest space analysis

  • statistical technique by Canter
  • data about many crime scenes and offender characteristics are correlated
  • themes: instrumental opportunistic, instrumental cognitive, expressive impulsive
• geographical profiling

  • analyses locations of connected series of crimes
  • considers where crimes committed, spatial relationships, how this may link to offender's place of residence
• circle theory

  • Canter and Larkin
  • if crimes are similar in nature and plotted on a map may be possible to join to form circle, criminal would live in centre - marauder
  • commuters - travel to another location, may also commit crimes within defined circles
• criminal geographic targeting (CGT)

  • Rossmo
  • 3D map showing probability of offender residence
  • jeopardy surface
• scientific basis of approach

  not as scientific as claimed

  • uses objective statistical techniques and computer analysis (appears scientific)
  • BUT data used to drive systems is based only on caught offenders, doesn't tell us much about unsolved crime
  • also, someone has to develop the systems and may do it wrong

  potential to be scientific, but inevitably biased
• usefulness of investigative psychology

  is it useful?

  • Copson surveyed 48 UK police forces - 75% said profilers advice useful, only 3% said advice actually helped identify offender
  • most said they'd use again

  may not be useful in catching, but does have slight benefits
• lack of success of circle theory

  Canter and Larkin study

  • 91% identified as marauders - if almost all not v useful as classification

  Pethrick

  • pointed out flaws - if home not in centre may look in wrong place, circles are oversimplistic may be ellipsis or other

  little usefulness
• lack of value in geographic profiling

  issue

  • can't distinguish between multiple offenders in one area
  • limited to spatial characteristics, no personality
  • not more useful than simple method of pins on map to see pattern