3 - Bottom-up Approach To Offender Profiling Flashcards
Outline the bottom-up approach
Aim - generate a picture of the offender, including their likely characteristics, routine behaviour, and social background.
This is achieved through systematic analysis of evidence left at the crime scene. Does not begin with fixed typologies, instead the profile is data-driven and emerges as the profiler engages in rigorous scrutiny of the details of the offence.
Bottom-up profiling is far more grounded in psychological theory than the top-down approach.
How does investigate psychology work?
Establish behaviours that are likely to occur at certain crime scenes - create a statistical database which then acts as a baseline for comparison.
Specific details of an offence can then be matched against this database in order to reveal statistically probable details about the offender (their personal history, family background etc.).
Can also help determine whether multiple offences are linked and likely to have been committed by the same individual.
Define interpersonal coherence
The way in which an offender behaves at the crime scene, including how they interact with the victim, may reflect their behaviour in everyday situations.
For example, whilst some rapists want to control and humiliate their victim, others can be apologetic. This might tell the police how the offender relates to women more generally.
Define forensic awareness
Individuals who have made an attempt to ‘cover their tracks’ (i.e. hide the body/murder weapon or clean the crime scene).
Their behaviour may indicate that they have been the subject of police interrogation in the past, or even that the police already have their DNA or fingerprints on file.
What concepts are key in investigative psychology?
Interpersonal coherence
Forensic awareness
The significance of time and place of the crime is also a key variable and may indicate where the offender lives
Outline geographical profiling
The study of spatial behaviour in relation to crime and offenders.
Focuses on the location of the crime as a clue to where the offender lives, works and socialises. Relevant data includes the crime scene, local crime statistics, local transport, and geographical spread of similar crimes.
The assumption is that a serious offender will restrict their criminal activities to an area that they are familiar with, and the offender’s base will therefore be in the middle of the spatial pattern of their crime scenes.
Earlier crimes are likely to be closer to the offender’s base than later crimes. As an offender becomes more confidence they will often travel further from their comfort zone.
What are the two models of offender behaviour?
The marauder - operates close to their home
The commuter - likely to have travelled a distance away from their home
What else does the spatial pattern of a crime reveal?
Whether the crime was planned or opportunistic, as well as other important facts about the offender such as their mode of transport, employment status, approximate age, etc.
What are the advantages of the bottom-up approach?
+ Content analysis of 66 sexual assault cases conducted. Characteristics were identified as common in most cases, such as use of impersonal language and lack of reaction to the victim. This characteristics will occur in different patterns in different people so can help establish if a series of offences were committed by the same person.
+ Argued that bottom-up profiling is more scientific than top-down profiling because it is more grounded in evidence and psychological theory and less driven by speculation and hunches.
+ Bottom-up profiling, unlike top-down profiling, can be applied to a wide variety of offences, such as burglary and theft, as well as murder and rape.
What are the disadvantages of the bottom-up approach?
- Significant failures when using bottom-up profiling. In 1992, 21 year old Rachel Nickell was stabbed 47 times and sexually assaulted in a frenzied attack on Wimbledon Common. In 2008, following examination of forensic evidence, Robert Napper was convicted of the murder. He had been ruled out early on in the initial investigation because he was several inches taller than the profile had said the offender would be.
- 48 police forces surveyed and found that advice provided by a profiler was judged to be useful in 83% of cases, but in only 3% of cases did it lead to accurate identification of the offender.
- Found that chemistry students produced a more accurate offender profile than experienced senior detectives.
