Offender profiling - bottom-up approach

What is the bottom-up approach?

profilers work from evidence collected from the crime scene to develop hypothesis about the likely characteristics, motivations and background of the offender. Offenders are not categorised

What is investigative psychology?

an approach that aims to establish patterns of behaviour that are likely to occur and co-exist across crime scenes to determine if crimes are linked (committed by the same offender)

How does investigative psychology use statistical databases?

it develops large databases of offender and offence details that act as baselines for comparison. New crimes are matched against this data to identify patterns and reveal important information about the offender e.g social background

What is interpersonal coherence?

the idea that the way an offender behaves at a crime scene reflects their behaviour in everyday life and relationships

Why is ‘time and place’ important in investigative psychology?

it gives clues about where the offender might live or work

What is forensic awareness?

when offenders show knowledge of forensic techniques techniques, suggesting they may have committed crimes before or have experience with the criminal justice system

What is geographical profiling?

the use of locations of linked crime scenes to make inferences about the likely home or operational base of the offender (crime mapping)

What does geographical profiling assume about serial offenders?

they restrict their crimes to areas they are familiar with

What is meant by the ‘centre of gravity’?

the central point of a spatial pattern of crimes, likely to be close to the offender’s base

How does the number of offences affect geographical profiling accuracy?

the more offences committed, the clearer the spatial pattern becomes

What are the two models in Canter’s Circle Theory?

the Marauder model and the Commuter model

What is the Marauder model?

the offender commits crimes within a geographical area surrounding their home base

What is the Commuter model?

the offender travels from their home to another area to commit crimes

How is the fact that the bottom-up approach can lead to mistaken identity and wrongful suspicion a limitation of the approach?

because profiling can become self-fulfilling, narrowing investigations too early and reflecting investigator bias rather than objective evidence. This can increase the risk of wrongful suspicion and or wrongful conviction

Give an example of this limitation

for instance, in the investigation into the murder of Rachel Nickell, profilers created a highly specific behavioural profile which led police to focus almost entirely on Colin Stagg despite lack of coherent evidence. The real offender, Robert Napper, remained free for years because he did not match the profile

How is the fact that the bottom-up approach has demonstrated effectiveness in real-life investigations a strength of the approach?

because it supports the scientific credibility of bottom-up profiling, showing that when applied rigorously, it can generate precise insights that enhances the method’s external validity and real life application.

Give an example of this strength

for instance, in the case of the ‘railway rapist’, John Duffy, David Canter created a profile based on systematic analysis of crime-scene data and geographical patterns. His predictions about Duffy’s characteristics, including his marital problems and interest in martial arts, were highly accurate

How is the fact that the bottom-up approach to offender profiling considers a range of different suspects, trying to ensure that the right person is identified a key advantage?

because it helps prevent miscarriages of justice such as a person being found innocent even in a case that they are guilty, vice versa

Give an example of this advantage

for example, it does not force detectives into rigid categories like organised/disorganised (like the top-down approach) preventing tunnel vision e.g ignoring evidence that doesn’t fir the classification and stereotyping

How is the fact that the bottom-up approach is applicable to a wide range of criminal offences a further advantage?

because it doesn’t limit the usefulness of the bottom-up approach and can be useful in real-life situations (such as detective work) meaning it has real-life application

Give an example of this advantage

for instance, the bottom-up approach can be used to investigate smaller crimes such as burglary and theft as well as serious offences such as murder and rape