The Bottom-Up Approach

Question 1

What is the Bottom-Up approach?

Answer 1

• Aims to generate a picture of the offender (e.g characteristics, routine and social background) through analysis/evidence at the crime scene
• Unlike the top-down approach it does not begin with fixed typologies
• Profile is data driven (much more grounded in psychological theory)

Question 2

What is Investigative Psychology?

Answer 2

• Applies statistical procedures/psychological theory to the analysis of crime scene evidence
• Aim to establish patterns of behaviour in order to develop a statistical database which acts as a baseline for comparison
• details of an offense, can be matched against this to reveal important details about the offender and whether a series of offences are linked

Question 3

What is the concept of Interpersonal Coherence?

Answer 3

• The way the offender behaves at the crime scene may reflect the way they behave in everyday life
• E.g some rapists want to humiliate their victims whereas some are more apologetic (Dwyer) may reflect their views regarding gender generally
• Time and place are key variables
• forensic awareness describes those who have been the subject of police interrogation as they be more mindful of covering their tracks

Question 4

What is Geographical Profiling?

Answer 4

• Uses info about the location of linked crime scenes to make inferences about the home of the offender: crime mapping
• Based on spatial consistency (people commit crimes in a limited space)
• assumes serial offender ‘work’ in areas familiar to them and provides investigators with a ‘centre of gravity’ includes offenders base

Question 5

What is Canters Circle Theory?

Answer 5

• Pattern of offending forms a circle around the offenders home base and leads us to describe offenders in two ways:
• The marauder (operates close proximity to home base)
• The Commuter (travels away from residence to commit crime)
• Gives insight into the nature of the offense e.g planned or opportunistic, also may reveal factors e.g mode of transport, employment status etc

Question 6

How did Canter come up with his theory?

Answer 6

• assisted police in the capture of John Duffy who carried out 24 sexual attacks on women and 3 murders near railway stations
• Canter analysed geographical info and was able to draw up an accurate profile
• Correctly assumed where he lived, his marital status, his height and certain physical feature e.g acne

Question 7

What is the evidence for the Bottom-up Approach?

Answer 7

• Canter and Heritage analysed 66 sexual assaults cases (smallest space analysis)
• Several behaviours were identified as common e.g impersonal language
• Each individual displayed a characteristic pattern of behaviours
• Supports basic principles of investigative psychology - people are consistent in their behaviour

Question 8

What is further research support for geographical profiling?

Answer 8

• Lundrigan and Canter, using smallest space analysis, 120 murder cases involving serial killers
• Found spatial consistency in the behaviour of the killers
• Location of each body disposal site created a ‘centre of gravity’ which is likely their home base

Question 9

What is one limitation of geographical profiling?

Answer 9

• May not be sufficient on its own
• It is dependant on the quality of data the police can provide which is not always accurate or reported (estimated 75% of crimes not reported at all)
• calls into question the utility of an approach that relies on the accuracy of geographical data
• May not be enough to catch an offender