Case Study - John Duffy Flashcards
Intro
Canter - Metropolitan police to draw a profile on ‘the Railway Rapist” who had been raping and murdering girls in the UK.
Most women targeted at railway stations around London.
Canter technique
Canter used geographic profiling to study the location of the crimes going back over 4 years. This helped pin down where the attacker lived. The pattern discovered suggested the killer was a Marauder who operated out of a home base.
Profile created
The profile Canter created said he was married with no children and had marriage problems; he was physically small with feelings of unattractiveness and lived in Kilburn or Cricklewood.
Actual profile
This offender profiling was found to be accurate as Duffy lived in Kilburn, was married, infertile and separated from his wife, was 5’4” and had acne.
Bottom-up
The Bottom-Up approach was successful as criminal acts in a consistent way and their behaviour can offer clues about their non-criminal lifestyle. There are clues in speech patterns, interests, obsessions and ways of behaving. Therefore enabling Canter to make a precise enough profile for Duffy.
Violent crimes reveal how the offender deals with people. 2 themes:
1: How prepared the offender is willing to relate to the victim, which can indicate previous attempts at relationships.
2: The level of dominance: In Duffy’s case this was minimal therefore indicating a weak individual who was insecure.
Breakthrough
This came when:
- look at the cases over 4 years
- lay on map
- overlay using acetate.
Breakthrough revealed
distinctive patterns in locations and types of crimes.
Allocated Canter to speculate where Duffy lived.
Later developed into his circle theory of crime. Then into a further hypothesis where he called his perpetrators “Marauders” or “Commuters” - strike from home or travel away.
Duffy = Marauder.
This was the first attempt to:
Attempts to use behavioural characteristics to search for criminals instead of using purely forensic evidence.
Profile meant
There were nearly 2000 linked to the crime by blood group but the factors from the profile allowed.
Duffy to be drawn from the database as the only one who lived in Kilburn area of London, worked as carpenter on railway and right age.
Arrest
Surveillance team watched Duffy and arrested him for suspicious activities.
Weapons effect
A strong chance the knife generated a weapons effect as the victims had varying ideas of appearance and Duffy was a lot shorter than they made him out to be.
Testimony
Testified in front of jury at Mulcahy’s trail to give evidence to clear his conscience. = accomplice
Prison psychologist
Confessed responsible to many more, admitted about accomplice.
25 offences between 1975-1986.
Convicted of…
Duffy was convicted of 2 murders and 5 rapes, he later confessed to more rapes and revealed collaborator.
