The bottom-up approach

Question 1

aim of bottom up approach

Answer 1

to generate a picture of the offender through systematic analysis of evidence at the crime scene. The profile is data-driven.

Question 2

Investigative psychology

Answer 2

Apply statistical procedures to the analysis of crime scene evidence. Aim is to establish patterns of behaviour that are likely to occur across crime scenes. Develop a statistical database which can help determine whether a series of offences are likely to have been committed by one offender.

Central to the approach is:
interpersonal coherence – way an offender behaves at crime scene gives clues as to how they behave in real life.
Significance of time and place is a key variable – may indicate where offender lives.
Forensic awareness also describes those individuals who have been the subject of police interrogation before.

Question 3

geographical profiling

Answer 3

Geographical profiling uses the location of linked crime scenes to infer the likely home base of an offender, known as crime mapping. It is based on the principle of spatial consistency—offenders commit crimes within areas they know well.

According to Canter’s circle theory, the pattern of offences often forms a circle around the offender’s home base, known as the centre of gravity.

Offenders are classified as:
Marauders – operate close to home.
Commuters – travel away from home to offend.

Question 4

Evaluation of bottom-up profiling (brief)

Answer 4

strength - evidence for investigative (canter and heritage)
strength - evidence for geographical (lundrigan and canter)
weakness - geographical insufficient on its own

Question 5

strength of bottom-up profiling

Answer 5

😊 evidence supports the use of investigative psychology. Canter and Heritage analysed 66 sexual assault cases using smallest space analysis. They found common behaviours (e.g., use of impersonal language), with each offender showing a consistent pattern. This supports the idea that offenders are consistent in their behaviour, a key principle of investigative psychology. However, case linkage relies on the database of solved crimes, therefore the usefulness of investigative psychology is limited by unsolved offences.

😊 evidence supports geographical profiling. Lundrigan and Canter collated information from 120 US murder cases. Smallest space analysis revealed spatial consistency in the behaviours of the killers. Body disposal sites formed a ‘centre of gravity’ near the offender’s home. The effect was more noticeable for marauders. This supports the validity of geographical profiling being used to identify an offender.

Question 6

weakness of bottom-up profiling

Answer 6

🙁 geographical profiling may be insufficient on its own. The effectiveness of geographical profiling is reliant on the quality of police data. Recording of crime is not always accurate and an estimated 75% of crimes go unreported to the police in the first place, reducing the reliability of geographical information. Even if this data is accurate, critics claim other factors are just as important in creating a profile, such as timing of the offence and the age and experience of the offender. This suggests that geographical profiling may be more useful when used in conjunction with other techniques.