The 'wicked soulmates'

The friends turned onto a path of unimaginable evil

David Mulcahy and John Duffy's gruesome path to murder began with a series of rapes and attempted rapes which got increasingly more violent.

The two were childhood friends, but the "wicked bond" that developed between them was broken for good last November when Duffy named Mulcahy as his partner in crime.

He (Mulcahy) was the instigator and prime mover in the murders

Mr Mark Dennis, prosecuting

Duffy was caught and jailed for life in 1988 and told he would never be released for murdering Alison Day, 19, and Maartje Tamboezer, 15 and a series of rapes.

Mulcahy, meanwhile, continued to live an apparently normal life with his wife and four children in north London.

Killing spree

On Friday, the second half of an evil duo was finally brought to justice, with Mulcahy being found guilty of all the charges - three murders, seven rapes and five charges of conspiracy to rape.

The pair's heinous crimes spanned a period of four years in the 1980s.

Alison Day was murdered

Dressed in balaclavas and carrying knives, they hunted down and raped 15 women, killing three of them, between 1982 and 1986.

Most of the women, aged between 15 and 32 years, were targeted at railway stations in and around London, others were attacked on Hampstead Heath in north London.

'Bullied at school'

Just how a young friendship could have degenerated into a secret life of violence, rape and murder has perplexed crime experts.

One theory is that bullying which Mulcahy and Duffy endured as schoolboys may have been the trigger which made them kill and rape.

It is likely that the pair developed a severely psychotic side to their personalities at an early age, and preyed on victims to rid themselves of the pain bottled up inside, one expert has said.

A shared loneliness drew them together on their first day at Haverstock secondary school in North London.

When he was just 13, Mulcahy was suspended from school for beating a hedgehog to death in the playground with a plank of wood, then trampling on its head.

Mulcahy photographed at a police station in 1984

Duffy was laughing at his side as he did it.

The pair became inseparable, increasingly playing truant from school.

Even after they were both married, Mulcahy and Duffy still spent considerable amounts of time together, particularly at night, when they would go out and drive around.

Night-time 'hunts'

They would go on "hunting parties" - looking for lone women to rape, and, eventually, to kill as well.

Mr Mark Dennis, prosecuting, told Mulcahy's trial: "As they fed their new-found predilections they treated their victims as objects rather than persons."

It was "only a comparatively small step" between the violence of the rapes and killing - and Mulcahy was the first to take it.

"He was the instigator and prime mover in the murders, and the one for whom the sexual abuse had become insufficient to satisfy," said Mr Dennis.

He liked women to be at the kitchen sink where they should be or in bed

Former colleague of Mulcahy

Duffy himself said Mulcahy was as excited like a schoolboy after killing their second victim - a 15-year-old girl.

Mulcahy's contempt for women was noted at a north London minicab firm where he used to work shifts.

"He liked women to be at the kitchen sink where they should be, or in bed," said Lola Barry, a controller at the cab firm.

She said Mulcahy had once crept up behind her in the office.

"He actually got me round the neck, saying 'How does that feel - are you scared?' "

'Jekyll and Hyde' character

Few people living in north west London where Mulcahy and his wife lived remember the killer.

But those who do now also believe they had met a Jekyll and Hyde character.

Anne Simpson, 53, said David and his wife Sandra appeared to be a happy couple and were affectionate in public.

"I for one was shocked when he was first arrested in the late 80s," she said.

His wife had remained loyal to Mulcahy despite the fact by 1988 he had been arrested three times in connection with the rapes and murders.

The reality of those crimes were chillingly retold during Mulcahy's trial at the Old Bailey, as all but one of the rape victims re-lived their ordeals.

Each woman was traumatised by her terrifying experiences - some had not even told their husbands, partners or families what they suffered.