Offender profiling: bottom-up approach Flashcards
Basic idea
Rather than top-down, we can instead work up from the basic evidence collected from crime scene to build hypothesis about the offender’s characteristics, routines and social background.
Investigative psychology (IP)
Originated in the UK, and is an attempt to apply statistical procedures and psychological theory to offender profiling - to establish patterns of behaviour and develop a statistical database for comparison.
uses smallest space analysis, which shows the ‘closeness’ of various traits.
Interpersonal coherence
the idea that an offender’s behaviour at the scene of the crime will be similar to how they act in other situations.
Significance of time & place
the idea that we can predict an offender’s home by looking at a map of their crimes
Forensic awareness
the fact that offenders who have dealt with the police before may attempt to cover up their crimes or hide evidence.
Geographical profiling (GP)
Rossmo (1997) based this idea on spatial consistency - the idea that an offender’s base and possible future behaviour can be based on the geographical location of their previous crimes. (crime mapping)
How does it work?
Detectives & psychologists will mark an offender’s crimes on a map, and with reference to time, examine the spread of offences to build a ‘jeopardy surface’ based around the centre of the map and where the offender will likely strike next.
Canter & Larkin (1993) ‘circle theory’
said that there are two types of offender: marauders (who operate close in proximity to their home) and commuters (who travel a distance away). Such spatial decision making can also tell us about the planning of their crimes as well as their ‘mental maps’ & schemas.
Evaluation strength: IP support Canter & Heritage (1990)
found common characteristics such as impersonal language varied in their use by each offender in a smallest space analysis of 66 sexual assaults. This shows that the model can be used to link offences and show how more than one can be committed by the same person which makes the approach more valid.
Evaluation strength: GP support Lundrigran & Canter (2001)
Smallest space analysis found evidence of spatial consistency and a clear ‘centre of gravity’ where the offenders home was usually located.
Evaluation strength: applies to wider range of offences
smallest space analysis and spatial consistency can be used to investigate burglaries or thefts as well as rape and murder.
Evaluation weakness: some cases have failed
Copson (1995) surveyed 48 police forces and found although they said bottom-up approach was useful in 83% of cases, it only lead to accurate identification of the offender in 3% of cases.
