John Duffy was a brutal rapist and killer who struck lone women at
railway stations throughout the South East and mainly North and West
“We would have balaclavas and knives. We
used to call it hunting. We did it as a bit of a joke. A bit of a
game." - John Francis Duffy
was at first thought to have carried out his heinous crimes alone and
was sentenced to life imprisonment for the murders. But police were
sure that he had an accomplice.
Only after 15 years did the advance of forensic science allow them to
arrest David Mulcahy, a childhood friend of Duffy, who was eventually
convicted. This case saw the first use in Britain of "Psychological
However, Mulcahy still protests his innocence after stating that Duffy implicated him in the murders.
John Duffy and David Mulcahy had been lifelong friends since their days
together at school in Haverstock, north London.
They both shared an early sadistic streak for tormenting and torturing
animals starting with a hedgehog, which Mulcahy beat to death with a
plank when he was aged just thirteen.
they got older the boys began to transfer their sadistic and
misogynistic tendencies to women, fuelling each other’s dark sexual
The pair, both building workers from Hampstead, most likely got the
idea to attack lone women when they realised how quiet areas were
around railway stations at night.
It is baffling to understand how a young friendship could have
degenerated into a secret life of violence, rape and murder. One theory
is that bullying, which both Mulcahy and Duffy endured as schoolboys,
may have been a key factor in driving them to rape and kill.
Whatever the trigger, the two boys had developed a severely psychotic side to their personalities at an early age. As he grew older, Duffy married and became a martial arts fanatic.
As they got older the boys began to transfer their sadistic and misogynistic tendencies to women, fuelling each other’s dark sexual fantasies.
Their brutal crimes began on July 1st, 1982, when the pair attacked and violently raped a twenty three year old woman in Hampstead, North London. Over the next four years a further 18 women were to be attacked.
Despite John Duffy being known to the police as a violent man - after assaulting his wife and being found carrying a knife - he was still able to carry out a string of sexual assaults and commit two murders over a fifteen month period.