top-down vs bottom-up profiling

top-down

• starts with information about the offender - used to create templates about future scenes

development

• American approach of profiling

• first tested by the FBI

• conducted in depth interviews of 36 sexual serial killers - cross referenced this with scenes and police interviews

• found that information from interviews could be classified as organised or disorganised

types of offenders

• organised (planned crimes): targeted victim, intelligent offender, adolescent onset, older, can maintain personal relationships

• disorganised (spontaneous crimes): not known to victim, early onset, younger, less socially competent, potential past drug offences

stages of constructing a profile

• data assimilation - review evidence

• crime scene classification - organised vs disorganised

• crime reconstruction - hypotheses (sequence of events, victim’s behaviour, etc)

• profile generation - hypotheses is linked to likely offender

bottom-up

• starts at the crime scene

• bases profile on behaviour pattern see in other scenes and everyday behaviour of offender

• interpersonal coherence: how the offender behaves at the crime scene (e.g. interactions with the victim)

• forensic awareness: involvement with prior investigation which can impact effectiveness at covering evidence

development

• British approach of profiling

geographical profiling

• using information about the location of linked crimes to find the home/operational base of the offender (‘crime mapping’)

• principle of spatial consistency: people commit crimes within a geographical space

• Canter’s circle theory: the offending circles around the base (point to a centre of gravity which is the likely home base)

types of offenders

• marauders: crimes are in close proximity to home base

• commuters: offenders travel away from base

• types give insight into the nature of the crime (planned/spontaneous) and personal factors about the offender (e.g. employment)