Bottom-up approach to profiling

Bottom-up profiling

• the profile is ‘data-driven’ and build as the investigtors scrutinise the offence

• uses past data from similar crimes to build the picture of the offender

Two elements:

• investigative psychology

• geographical profiling

Investigative psychology

• statistical procedures + psychological theory to analyse crime scene evidence

• aims to establish patterns of behaviour that co-exist across crime scenes

• this data is used to create a database as a baseline for comparison

• specific details of an offense are then latched to the data base to reveal offenders characteristics

Egger (1999)

• Egger argues that Canters work is partially based on some of the key assumptions about the interactions between offenders and their victims

  1. interpersonal coherence

  2. time and place

  3. criminal characteristics

  4. criminal career

  5. forensic awareness

• with these primary principles in mind, bottom-up profilers can build a picture of the offender often by also using other techniques, usually statistical in nature, which enables them to objectively analyse the evidence

Interpersonal Coherence

• The way in which an offender behaves at the crime scene may reflect on their everyday behaviour

• there is a consistency in how they interact with the victim and with others in their daily lives

Time and place

the time and location of an offender’s crime will communicate something about their own place or residence/employment

Criminal characteristics

• characteristics about the offender can help to classify them

• this can help a police investigation by narrowing the field of search

Criminal career

crimes tend to be committed in similar fashion by offenders and can provide indication of how their criminal activity will develop

Forensic awareness

• this term defines those who have had previous experience of police interrogation

• the way they behave may reveal how mindful they have been about covering their tracks

Geographical 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

• first described by Kim Rossmo (1997)

• uses the location of linked crime scenes to make an inference about the likely home or base of an offender

Principles of geographical profiling

• locatedness

  • in any violent crime it may be that several locations are relevant

  • e.g. an offender may meet a victim, attack, dispose etc. in different locations

  • all these locations are part of building an accurate picture

• systematic crime and location choice

  • this is the assumption that crime scenes are not random

  • the offender will likely have some kind of connection with the area or at least a familiarity

• centrality

  • as crime scenes are likely to occur in a familiar area to the offender, this means that crime scenes tend to cluster

  • there are two types of offender that can require further analysis - commuters and marauders

• comparative case analysis

  • this is the assumption that the crimes are being committed by the same offender and therefore increases the precision of the geographical profiling

Canters Circle Theory (Canter and Larking 1993)

• proposes 2 models of offender profiling

  • the marauder - operates close to their home base

  • the commuter - likely to travel further away from their usual residence

• suggests the pattern of offending behaviour will form a circle around the offenders usual residence

if investigators can understand this Spatial Pattern they create a ‘center of gravity’ which will usually include the offenders base

it can also suggest where the offender will strike next - the Jeopardy Surface

AO3 - weakness - other factors important

P = a weakness of the geographical profiling approach is that it can be argued that there are other factors that need to be taken into account

EX = other factors like the offenders psychological characteristics need to be taken account to get a holistic view of the offender as just focusing on the location may not show the whole picture. Concentrating on the location may cause an investigator to miss important information if used in isolation

EV = Canter and Heritage (1990) carried out a content analysis of 66 sexual assault cases using the Smallest Space Analysis - a computer program that identifies correlations across patterns of behaviour and several characteristics were identified as common in most like the use of impersonal language and lack of reaction to the victim.

C = however, this research was conducted by Candor and therefore the findings could be said to be bias since it suffers from research bias.

LB = despite this, although location is an important factor in offender profiling, it is naive to base the entire investigation around this singular factor and other factors need to be taken into account to build up an accurate profile.

AO3 - strength - evidence

P = one strength of geographical profiling is that there is research evidence to support it

EV = Lundrigan and Canter (2001) collated information from 120 murder cases involving serial killers in the USA and analysis revealed spatial consistency in the behaviour of the offenders. The location of the body disposal site was in a different direction than the previous one, creating a center of gravity. The effect was more noticeable for offenders who travelled short distances

EX = this supports Canter’s claim that spatial information is a key factor in determining the base of an offender

C = on the other hand, this research can be criticised for having researcher bias as Canter both suggested geographical profiling and carried out the research. Furthermore, the sample is very specific as it only involves murder cases from America and therefore the success of geographical profiling for these cases may not be generalisable for other types of case or outside the USA

LB = Despite this, geographical profiling has been shown to be accurate in cases like John Duffy - the Railway Rapist - and so is an effective way of profiling the offender.

AO3 - support - works for different crimes

P = another strength of the geographical profiling approach is that it helps to locate offenders of many different types of crime, unlike the top-down approach which is limited to violent crimes

EV = for example, geographical profiling can be used to locate the likely homes of burglars given that they concentrate their crimes in a familiar place, often close to their homes.

EX = smallest space analysis and the principle of spatial consistency can be used across a range of crimes, from burglary to murder meaning that this approach is helpful for a wide range of crime

C = however, although geographical profiling is successful for a wide range of crimes, there are mixed results for this method with some significant failures like Rachel Nickell.

LB = geographical profiling tends to be a reliable approach for profiling an offender and for a range of crimes however we must be cautious to rule out suspects based purely on this approach