Bottom-up approach

• The bottom-up approach: Profilers work up from evidence collected at the crime scene to develop hypotheses about the likely characteristics, motivations and social background of the offender.
• • Unlike the US top-down approach an investigation that is using the British Bottom-up approach does not begin with fixed typologies
  • Instead the profile is data driven and emerges as more evidence is analysed
  • Bottom up approach is more grounded in psychological theory than the top-down approach
• Investigative psychology.

  • This may help determine whether a series of offences are linked
  • Central to the approach is interpersonal coherence. This is hwo an offender behaves at the scene and interacts with the victim may reflect their behaviour in everyday situations.
  • The significance of time and place is also a key variable which may indicate where an offender lives
  • Also forensic awareness describes those individuals who have been interrogated by the police before, may be more careful in their crime
• Investigative psychology: a form of bottom up profiling that matches details of the crime scene with statistical analysis of a typical offender behaviour patterns based on psychological theory.
• Geographical profiling- A form of bottom-up profiling based on the principle of spatial consistency- that an offenders operational base and possible future offences are revealed by the geographical location of their previous crimes.
• Geographical profiling

  • the assumption is that serial offenders will restrict their offences to areas they are familiar with, so understanding this allows investigators to identify a centre of gravity by plotting crime scenes on a map (Canters circle theory)
  • The distribution of offences can be categorised into
  • the marauder- who operates in close proximity to their home
  • the commuter- who is likely to have travelled a distance away from their usual residence.
• Geographical profiling:

  Crime mapping can allow investigators an insight into the nature if the offence, whether it was planned or opportunistic as well as potentially revealing employment status, approximate age, mode of transport- these can all help identify the offender.
• A03: evidence to support investigative psychology

  • Canter and Heritage conducted an analysis of 66 sexual assult cases using smallest space analysis. Several behaviours were identified as common in different samples of behaviour, such as the lack of reaction to the victim.
  • Each individual displayed a characteristic pattern of such behaviours and this can help establish whether two or more offences were commited by the same person - case linkage.
  • This supports one of the basic principles in investigative psychology that people are consistent in their behaviours
• A03: CC: However, case linkage depends on the data base and this will only consist of solved historical crimes. The fact that they were solved could mean they were relatively straight forward to link in the first place

  • Suggesting that investigative psychology may tell us little about crimes that may have few links between them, leaving them unsolved.
• A03: evidence to support geographical profiling

  Lundrigan and Canter collected inofrmation from 120 murder cases involving serial killers in the US. Smallest space analysis revealed spatial consistency in the behaviour of the killers. The location of each body disposal created a centre of gravity which located the offenders base . The effect was more noticeable for offenders who travelled short distances, marauders
• A03: Geographical profiling may be insufficient on its own.

  • the success of geographical profiling may rely on the quality of the data the police can find.
  • Unfortunately 75% of crimes are estimated to not even be reported to the police so this begins to question the accuracy of geographical data
  • Even if this is correct, critics argue other factors are just as important at building the offenders profile- timing of offence, experience of the offender.
  • This suggests geographical profiling alone may not be helpful in finding the offender