Forensics - Offender profiling

Question 1

What is offender profiling?

Answer 1

A method of identifying the perpetrator of a crime based on analysis of the nature of the offence and the manner in which it was committed.

Question 2

What is an offender profile?

Answer 2

Outlines the type of person likely to have committed a crime.
They are used to shorten the list of suspects.

Question 3

What is a dichotomy?

Answer 3

Two exclusive categories; organised or disorganised.

Question 4

What are the organised characteristics of a crime?

Answer 4

• Actions reflect planning and control
• Uses weapons and restraints that are planned
• Crime scene is in order, leaves few clues
• Victim is a targeted stranger

Question 5

What are the likely characteristics of the offender in an organised crime?

Answer 5

• In a skilled occupation
• Above average intelligence
• Married/co-habiting
• Socially and sexually competent

Question 6

What are the disorganised characteristics of a crime?

Answer 6

• No pre-planning
• Uses whatever weapons are available
• Crime scene is chaotic, leaves blood, fingerprints and murder weapon behind - little attempt to hide evidence
• Victim is random (convient)

Question 7

What are the likely characteristics of an offender in a disorganised crime?

Answer 7

• Unskilled occupation
• Low levels of intelligence
• Lives alone - near crime scene
• Sexually and socially inadequate

Question 8

What are the four stages in the construction of a top down profile?

Answer 8

1 - Data assimilation (profiler reviews evidence; crime scene, witness reports)
2 - Crime scene classification (either organised or disorganised)
3 - Crime reconstruction (hypothesis in terms of sequence of events)
4 - Profile generation (hypothesis related to the likely offender)

Question 9

What are the limitations to top down profiling?

Answer 9

• The original sample it is based on interviews 36 sexually motivated killers; small sample.
• Only applies to particular crimes such as serial crimes.
• Based on outdated models of personality.
• Classification is too simplistic; killers can be act-focused or process-focused, so there may be more categories.
• Evidence does not support the dichotomy - Canter analysed 100 cases of serial killings and found that most crime scenes include elements of both organised and disorganised.

Question 10

What hypothesis did Canter develop?

Answer 10

Criminal consistency hypothesis

• States that an offender’s behaviour when committing a crime is like their behaviour in their everyday life.
• Contains Interpersonal Consistency and Spatial Consistency

Question 11

What is interpersonal consistency?

Answer 11

The theory that the behaviour of the offender at the time of the crime will be similar to everyday life.
For example, ‘overkill’ indicates a perpetrator of a violent, sexual crime is likely to be on record for domestic violence.

Question 12

What is spatial consistency?

Answer 12

Locates the most probable location of the home of the offender from the distribution of the scenes of the crime.
It assumes criminal offences will occur in places the offender makes regular use of.

Question 13

What is distance decay?

Answer 13

The further from the home of the offender, the fewer crimes.

Question 14

What is circle hypothesis?

Answer 14

The majority of offenders’ homes can be located within a circle, with its diameter defined by the distance between the offender’s two furthermost crimes.

Question 15

What is the Marauder model?

Answer 15

The offender operates in close proximity to their home base.

Question 16

What is the commuter model?

Answer 16

The offender travels from home base to a location, eg. workplace, partner’s home, and operates in a circle pattern there.

Question 17

What is dragnet?

Answer 17

A computer package, based on Canter’s empirical research into the spatial behaviour of offenders.
It uses a series of crime locations and determines the most likely area for the perpetrator’s home.

Question 18

Who is John Duffy?

Answer 18

• The ‘Railway Rapist’

- 24 sexual attacks and 3 murders in the 1980s, around railway stations across North London.

Question 19

What from Canter’s profile turned out to be correct about John Duffy?

Answer 19

• Canter suggested he lived in an area near to the area of his first crimes; Duffy did live in the area he suggested.
• Canter said he had a knowledge of railways; Duffy worked for British Rail.
• Canter said he had previous criminal record for violence; Duffy raped his wife at knifepoint.

Question 20

What are the strengths of Bottom-Up Offender Profiling?

Answer 20

• Case of John Duffy supports the method; led to the capture of Duffy.
• Evidence supports geographical profiling being effective:
  analysis of 120 serial murder cases was conducted and found evidence for SPATIAL CONSISTENCY. The offender’s base was located in the centre of the circle created by their crimes.

However, this is only really useful for serial crimes.