Offender Profiling

Offender Profiling

1. Definitions

   • Blau (1974) deriving offender's likely characteristics from the way in which he or she committed a crime.
   • Rossmo (2000) the interpretation of crime scene evidence that can indicate the personality type of the person who committed the offence.
   • A to C equation: actions at the crime scene and characteristics of the offender.

2. Top-down approach. Use investigative experiences and base claims on their own and their colleagues' experiences.

   • FBI Approach
     • 1970s, developed for organised/disorganised typology.
     • 36 interviews with convicted serial killers. All consented to talk and all been caught so not generalisable.
     • Organised = kills onsite, disposes at another, brings weapon to scene with confident approach and leaves no evidence. Higher IQ, socially adequate, lives with partner, college educated.
     • Disorganised = kill and dispose on same site, use weapons available on site, attack out or nowhere and leave physical evidence. Lower IQ, socially inadequate, lives alone, low education.
     • Indicates the low/high IQ offender.
     • Problems;
       • Sample size too small.
       • Too simplistic - can't split in to one of two categories just dependant on behaviour at scene.
       • Susceptible to heuristics and decision making errors. Confirmation bias - just because seen before doesn't mean it will happen again.
       • Studies don't show FBI profilers to be any more accurate than other police officers.
   • Clinical Practitioner Approach
     • Use their personal experiences to assess and treat offenders in high/medium security units.
     • Base the claims on the offender on interactions with others in the units.
     • Same problems as with the FBI - only one practitioner can see so much.
     • Helpful approach when clear evidence that the person has a mental health problem.

3. Disparity between what is done in science and what is done in a legal case. Profiles cannot prove an individuals guilt, only used for investigative purposes.

4. Bottom-up approach. Use statistics and research, used in the UK as a whole.

   • Need a systematic, scientific approach in analysing crime and criminals.
   • The modern UK approach developed by environmental psychologist David Canter.
   • David Canter and case of series of rapes and murders carried out across London. First crimes related to routine activity and move from opportunistic to planned and weekends to weekdays.

5. Investigative Psychologists

   • Provide relevant information to the police.
   • Use information that the police know about.
   • Use 100s of cases to profile offenders and not just their own experiences.
   • Conduct research used by profilers and police evidence based models.
   • Conduct research in to how profiles are received and interpreted.
   • Evaluate profiles and help develop best practice for writing reports. Decision making process.
   • Three strands to this process: criminal actions and investigative inferences, investigative and legal processes and assessment of investigative and legal information.