bottom up profiling

the bottom up approach (British)

• profilers work up from evidence collected from the crime scene to build a picture of the offender and develop hypotheses about the likely characteristics, motivations, routine behaviour and social background of the offender

• avoids the fixed typologies used in the top down approach, more focused on psychological theory

• the profile is data driven and emerges as the investigator rigorously scrutinises the details of a particular offence

investigative psychology

• a form of bottom up profiling that matches details from the crime scene with statistical analysis of typical offender behaviour patterns based on psychological theories

• looks to establish patterns of behaviour that coexist across crime scenes, to develop a statistical ‘database’ of characteristics to act as a method of comparison for future crimes

• may link a series of offenders to the same offender, features of an offence can be matched against the database to suggest details about the offender, their history, family background etc

interpersonal coherence

• how an offender behaves at a crime scene and interacts with the victim may reflect their everyday behaviour

• Dwyer (2001) some rapists want to control and humiliate victims, and may show this in their everyday interactions with women, others are more apologetic and may be avoidant of women in everyday life

factors in investigative psychology- significance of time and place

• if a crime is committed at 5:15pm near an office block, the offender may work there and finish work at 5pm

• if the associated crimes are in a certain area, its likely the offender lives or works there

factors in investigative psychology- forensic awareness

• offenders may have been involved in police interrogation before

• behaviour at crime scenes may show they know how to cover their tracks

geographical profiling

• form of bottom up profiling based on spatial consistency, that an offenders operational base and possible future offences are revealed by the geographical location of their previous crimes, called crime mapping

• people tend to commit crimes in a limited geographical space

• used alongside investigative psychology to hypothesise how the offender is thinking and their modus operandi (habitual way of working)

• assumes serial offenders restrict their crimes to areas they’re familiar with, mapping their crimes can provide a ‘centre of gravity’, including offenders base and way of working (modus operandi)

circle theory- Carter + Larkin (1993)

• this pattern of offending tends to form a circle around the offenders home base, becomes more apparent the more offences there are

• distribution of offences labels offenders as 1 of 2 types:

1. the marauder- operates close to their home base

2. the commuter- travels away from their usual home base

• tells us if they planned the offence and things about the offender eg mode of transport, employment, approximate age

strength- John Duffy case supports effectiveness of bottom up profiling, showing data analysis can accurately predict offender traits

• psychologist Dan Canter used crime scene and geographical data to predict the ‘railway rapist’ would be a small, violent, right handed main in his 20s living in North London, Canter used geographical profiling to map the crimes and spot a centre of gravity in north London to direct police to one of their suspects

• when Duffy was caught, nearly all predictions matched, this accuracy shows data driven profiling can identify patterns of behaviour and geography to guide investigations effectively

• so Duffy case shows bottom up profiling can be a reliable, evidence based tool when applied systematically

limitation- Rachel Nickel case highlights major flaws in bottom up profiling + how reliance on psychological predictions can misdirect investigations

• Paul Briton’s psychological profile led police to target Colin Stagg, despite no physical evidence linking him, years later it emerged the killer was Robert Napper, by DNA previously ruled out due to being inches too tall to fit the profile

• shows how profiling can lead to confirmation bias and false assumptions, when profiles are treated as fact, they can lead to injustice, wasted resources and potentially further crimes which could’ve been avoided

• shows bottom up profiling isn’t always reliable and must be used with caution alongside solid evidence

strength- evidence supports investigative psychology

• Canter + Heritage (1990) conducted an analysis of 66 sexual assault cases using smallest space analysis, several behaviours were identified in most cases eg interpersonal language

• each individual displayed a characteristic pattern of such behaviour, helps link if 2 or more offences were by the same person (case linkage)

• supports one of the basic principles of investigative psychology, and the bottom up approach, that peoples behaviour is consistent

counterpoint- case linkage relies on a database

• but, the database is made up of only solved crimes which are likely to be those straightforward to link together, circular argument

• if crimes aren’t in the database, we cant link them and solve them too add to the database, becomes a vicious cycle

• suggests investigative psychology may tell us little about crimes that have few links between them and therefore remain unsolved

strength- evidence to support geographical profiling

• Lundrigan + Canter (2001) analysed 120 murder cases by US serial killers, smallest space analysis revealed spatial consistency in location of body disposals, a centre of gravity

• offenders leave home in different directions each time when dumping a body but created a circular effect, especially for marauders

• supports the view that geographical information can be used to identify an offender

limitation- geographical profiling may be insufficient on its own

• recording of crime isn’t always accurate, can vary between police forces and an estimated 75% of crimes aren’t reported to police, if geographical data’s missing or unreported, centre of gravity less clear

• even if crime data is correct, other factors eg timing of the offence, age and experience of the offender matter (Ainsworth 2001)

• suggests geographical information alone may not always lead to the successful capture of offenders

evaluation- mixed results

• Copson (1995) surveyed 48 police departments and found profilers advice was ‘useful’ in 83% of cases, suggests the approach is valid

• the same study revealed profiling only led to accurate offender identification in 3% of cases, Kocsis et al. (2002) chemistry students produced more accurate profiles using a solved case than detectives

• suggests offender profiling may have little practical value when it comes to solving cases