Offender Profiling- Bottom-up Approach Flashcards
What is the bottom up approach?
This approach doesn’t begin with fixed typologies. This profile is ‘data-driven’ and emerges as the investigator engages in deeper and more rigorous scrutiny of the details of the offence.
Profilers work from ev collected from the crime scene to develop hypotheses about the likely characteristics, motivations and social backgrounds of the offender.
Two of the techniques within the BO approach are investigative psychology and geographical profiling.
What is investigative psychology?
-IP matches details from the crime scene with statistical analysis of typical offender behaviour patterns based on psychological theory.
-the aim is to establish patterns of behaviour that are likely to occur across crime scenes. This helps to develop a statistical database which then acts as a baseline for comparison.
-specific details about offence/related offences can then be matched against this data base to reveal important details about offender (personality, history, family background etc). This may reveal whether a series of offences are linked in that they are likely to have been committed by the same person.
What are the three main features of the BU approach?
1.Interpersonal coherence - the way an offender behaves at the scene, including how they ‘interact’ with their victim, may reflect their behaviour in more everyday situations.
2.Time and Place - this may indicate where the offender is living or working.
3.Forensic awareness - certain behaviours might reveal awareness of police techniques and past experience.
John Duffy
-real-life example
-‘railway rapist’ assaulted 24 women, killed 3
-canter made a profile that nearly exactly matched Duffy.
-it was purely based things left at crime scene, DNA, witness
What is geographical profiling?
-GP is 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.
-it can be used in conjunction with psychological theory to create a hypothesis about how the offender is thinking as well as their modus operandi.
-the assumption is that repeat offenders will restrict their work to geographical areas they’re familiar with. Therefore understanding the spatial pattern of their behaviour provides investigators with ‘centre of gravity’ which is likely to include the offenders base. May also help investigators to guess where the offender is likely to strike next ‘the jeopardy surface’
Canters Circle Theory
It proposed two models of offender behaviour:
-the marauder - operates in close proximity to their home base
-the commuter - likely to have travelled a distance away from their usual residence
-the spatial decision making of the offender can offer the investigative team important insight into the nature of the offence. Was it planned or opportunistic? Also reveal other features such as modes of transport, employment, status and age.
Similarities between BU and TD
- used to narrow field of suspects
-assume that there’s pattern in an offenders behaviour which is not always the case
-use info from crime scene to make profile
