2. profiling bottom up approach

what is the bottom up approach

profilers work up from evidence collected from the crime scene to develop hypotheses about the likely characteristics, motivations and social background of the offender

• more data driven and emerged as the investigator engages in deeper and more rigorous scrutiny of the offence details

• grounded in much more psychological theory

two aspects of the bottom up approach

1. investigative psychology

2. geographical profiling

investigative psychology definition

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

aim

to establish patterns of behaviour that are likely to occur, or coexist, across crime scenes to develop a statistical database to act as a baseline for comparison

what is central to the approach

the concept of interpersonal coherence

• the way an offender behaves at the scene may reflect their behaviour in daily life

• ie some rapists are more apologetic which may tell the police something about how the offender relates to women more generally

other key variables

• significance of time and place - may indicate where the offender lives

• forensic awareness - an offender who has been the subject of police interrogation behaviour as their behaviour may denote how mindful they are of covering their tracks

geographical profiling definition

a form of bottom up profiling based on the principle of spatial consistency - an offenders operational base and possible future offences are revealed by the geographical location of their previous crimes (crime mapping)

what can it be used with

can be used in conjunction with psychological theory (like that informed by investigative psychology) to create hypotheses about how the offender is thinking as well as their modus operandi

what assumption is made

• serial offenders will restrict their ‘work’ to geographical areas they are familiar with

• so understanding the spatial pattern of their behaviour provides investigators with a centre of gravity that is likely to include the offenders base

what is it the basis of

canter’s circle theory

• the pattern of offending forms a circle around the offenders home bease

the distribution of offences leads us to describe an offender in one of two ways

1. the marauder - operates in close proximity to home base

2. the commuter - likely to have travelled a distance from their usual residence

what does spatial decision making tell us about an offender

• gives insight to the nature of the offence ie whether it was planned or opportunisticc

• reveals other important factors like their mode of transport, employment status and approx age

evaluation

1. research support for investigative psychology (& COUNTERPOINT)

2. research support for geographical profiling

3. insufficient

4. mixed results

research support for investigative psychology

• supported by empirical research

• canter analysed 66 sexual assault cases and identified consistent behaviour patterns, such as the use of impersonal language and lack of concern for victims

• recurring patterns suggest offenders show behavioural consistency meaning their actions can be analysed systematically to link crimes and identify suspects

• shows its a reliable and scientific method

counterpoint

• all crimes were solved so patterns identified may only apply to caught offenders

• as a result investigative psychology may tell us little about unsolved crimes which is when it would be most useful

• reduces generalisability and practical usefulness weakening claims it provides strong evidence for offender profiling

research support for geographical profiling

• canter analysed 120 murder cases and found an offenders base was often located at the centre of the circle formed by crime locations (the marauder pattern)

• shows offenders tend to commit crimes within a familiar area allowing police to predict likely home locations using spatial data

• supports it as an affective part of the bottom up approach

geographical info may be insufficient

• alone it may not be enough to identify offenders

• around 75% crimes are not reported and offenders may change locations based on opportunity, transport or experience

• if crime data is incomplete or inaccurate, predictions about offender location become unreliable weakening effectiveness when bottom up approach is used in isolation

mixed results

• usefulness of offender profiling is inconsistent

• copson found profiles were useful in 83% of cases but only helped identify a suspect for 3%, another study found students produced more accurate profiles than experienced detectives

• suggests profiling may be more helpful for understanding crimes rather than catching offenders, and expertise does not always improve accuracy

• questions practical application of bottom up approach in real investigations