Forensic - Making A Case - Creating A Profile

Aim: to test the reliability of orgainsed/disorganised typologies

Method: content analysis using psychometric method of multi-dimensional scaling applied to 100 cases to find out if features hypothesised to belong to each typology would be consistently and distinctively different

Key Results: twice as many disorganised crime-scene actions identified - disorganised offenders are easier to identify. 2 crime scene behaviours in organised typologies: body concealed 70% of time, sexual activity 75% of time. only sex acts and **** occur in +2/3 of disorganised cases; acts that occur most often in serial murder not distinctively different for each murder. 

Conclusions: instead of distinction between two types of serial murder, all crimes will have organised element to them, might expect from the fact killers not caught after 3 killings. distinctions between killers may be a function of the different ways they may exhibit disorganised aspects of their activities. Better way is to look at the individual personality differences between offenders

PSYCHODYNAMIC/BEHAVIOURIST/INDIVIDUAL DIFFERENCES

Evaluation Points: 

• reductionism vs. holism
• individual vs. situational 

Method issues:

• attrition of sample
• ethnocentric - only US cases

suggests better way - to look at individual differences. qualitative data - greater degree of understanding and elaboration of criminal behaviours. 

could be slightly reductionist when attributing actions to organised/disorganised offenders. no way of testing whether assumptions are true.

Aim: to identify a behaviour pattern from similarities between offences

Method: content analysis of 66 sexual offences, committed by 27 offenders, to find 33 offence variables that were clearly linked. i.e. var. 2 'suprise attack' possible to say yes or no to each variable. data subjected to smallest-space analysis.

Key Results: variable found central to 66 cases: vaginal intercourse, no reaction to the victim, impersonal language, surprise attack and victim's clothing disturbed. suggests pattern of behaviour. less central were four elements found to be important: attempted intimacy, sexual behaviour, over violence and aggression, impersonal interaction and criminal behaviour and intent.

Conclusions: usefulness of this method is that all five aspects have now been shown to contribute to all sexual offences, but in different patterns for different individuals. leads to understanding of how an offenders behaviour changes over a series of offences, or to establishing whether two or more offences were committed by the same person. This has become known as his '5-factor' theory.

PSCHODYNAMIC/BEHAVIOURIST/INDIVIDUAL DIFFERENCES

Evaluation Points:

• reductionism vs. holism
• individual vs. situational

Method issues:

• attrition of sample

all aspects have shown to contribute to to all sexual offences. leads to understanding of how behaviours change over series of crimes. establishes whether two or more offences were committed by the same person.

could be slightly reductionist when data is subjected to the small-space analysis. deterministic - can predict behaviour, assuming most will act in the same way

Nov 2000, John Duffy serving life for **** and murder of several women, confessed to committing 25 offences between 1975-86 including 22 attacks on 23 women aged between 15-32 with an accomplice, David Mulcahy. Women targeted at railway stations in and around London.

Canter's Preliminary Profile: possibly arrested sometime after 1983. Residence lived in the areas circumscribed by first 3 cases since 1983, probbaly lived there at time of arrest, probably lives with wife or girlfriend, no children. Age mid to late 20's, light hair, 5ft9, right handed. Occupation semi-skilled or skilled involving weekends and casual labour from July 1984 onwards, job most likely does not bring him into contact with public. Character keeps himself to himself, little contact with women, knowledge of railway system where attacks happen. Sexual activity variety of sexual actions suggests considerable sexual experience. Criminal record probably arrested sometime between October 1982 and January 1984, may have had nothing to do with **** but being aggressive or under influence.

This profile represents the first attempt to use behavioural characteristics to search for a criminal instead of purely forensic evidence from the crime scene. Victims may have experienced 'weapons effect' as knife was used to control them.