A.K.A.: "The Railway Killer" - "The Railway Rapist"
Classification: Serial killer
Characteristics: Serial rapist (7)
Number of victims: 3
Date of murders: 1985 - 1986
Date of arrest: February 3, 1999
Date of birth: 1959
Victims profile: Alison Day, 19 / Maartje Tamboezer, 15 / Anne Lock, 29
Method of murder: Strangulation
Location: North London, England, United Kingdom
Status: Sentenced to three life sentences, with a 30-year recommendation, on February 1, 2001
John Duffy and David Mulcahy (born 1959) are two British rapists and serial killers who together attacked numerous women at railway stations in the south of England through the 1980s. They are known as the Railway Rapists and the Railway Killers.
The first attacks
In 1982 a woman (KJ) was raped by two men near Hampstead station and subsequently eighteen more were attacked over the next year. More occurred through 1984 and then three were raped on the same night in 1985 in Hendon. Police set up an urgent workshop to try to find the perpetrators, called Operation Hart.
The name of Duffy, a martial arts instructor, was touted as a suspect among thousands of other names as he was on the sex offenders register following conviction for the rape of his wife. Rope found in his parents house linked him to the second murder victim. Mulcahy was also questioned due to his close friendship with Duffy but victims were still traumatised and unable to pick him out of an identity parade. Mulcahy was released for lack of evidence.
The switch to murder
On 29 December 1985, Alison Day, 19, was dragged off a train at Hackney Wick station by Duffy and Mulcahy and repeatedly raped. She was then strangled with a piece of string.
Police further stepped up their search for the attacker who had been coined by the press as the Railway Rapist. The death of Alison Day changed this moniker to the Railway Killer, a tag reinforced by the rape and murder of 15-year-old Maartje Tamboezer in West Horsley on 17 April 1986. As well as rape and strangulation, Maartje's body was set on fire. A month later on 18 May 1985, local TV presenter Anne Locke, 29, was abducted and murdered as she dismounted a train in Brookmans Park, Hertfordshire.
Police brought in a psychologist from the University of Surrey, Dr. David Canter, to help their inquiries. There had been no previous use of "psychological offender profiling" as it was known, but something fresh was required as three women had been murdered and numerous more raped, with little progress being made. Canter examined the details of each crime and built up a profile of the attacker's personality, habits and traits. While this continued, another attack took place as a 14-year-old girl was raped in a park (David Canter was a psychologist working in the field of geographical psychology at the time). This enquiry led him to set up Investigative Psychology in which he has become an acknowledged expert in the field.
As well as working together Duffy had started to rape alone and he was arrested while following a woman in a secluded park, he was questioned also about the spate of rapes and murders, and the next day charged on all counts. Police knew he had not committed the offences alone, but Duffy was not forthcoming about his accomplice.
Duffy went on trial in February 1988 and was convicted of two murders and four rapes, although he was acquitted of raping and killing Anne Locke. He was given a minimum tariff of 30 years by the judge, later extended to a whole life tariff by the Home Secretary. A European Court of Human Rights ruling later removed the right of politicians to reset sentence tariffs, and so Duffy's stay in prison was reverted to the original 30 years. He will be in prison until at least 2018 and the age of 69.
Much was made of the psychological profile constructed by Canter after the trial, as Duffy fitted 13 of the 17 observations made about the attacker's lifestyle and habits. Such profiling became immediately commonplace in policing thereafter.
The accomplice is found
Following his conviction, Duffy revealed to a forensic psychologist what the police knew already - that he had not attacked the women alone. However, he chose to reveal no more until 1997 when he implicated Mulcahy, a lifelong friend with whom Duffy had been inseparable since their days together at school in Haverstock, North London. Duffy also admitted his involvement in the attack on Anne Locke, although couldn't be re-tried for this under the double jeopardy rule.
However, Mulcahy - a married father of four - could still be implicated and following Duffy's claims, he was tracked for several months by police prior to his arrest and DNA-tests (which were not yet in use during the original investigation) also proved his involvement conclusively. In 2000, Duffy appeared at the Old Bailey as a witness against Mulcahy and gave detailed evidence over 14 days. It was the first time a highest-category prisoner had ever given evidence against an accomplice.
Mulcahy emerged through the trial from prosecution evidence as the chief perpetrator and the first to decide that sexual stimulation wasn't enough of a thrill any more, so turning to murder.
Mulcahy was convicted of three murders and seven rapes and handed 3 life sentences, with a 30-year recommendation. He was not later given a whole life tariff, as the ruling barring politically-set tariffs had been made by the time his case was due for review.
Duffy was convicted of 17 more rapes and received a further 12 years. Neither man is expected to ever be released from prison alive. Police suspect them of countless other sex attacks, some dating back to the mid-1970s, while Mulcahy is also suspected of attacks which took place after Duffy was jailed.
There has been occasional publicity for the pairing since Mulcahy's imprisonment, including newspaper claims that Duffy was paid 20,000 pounds in return for information about his accomplice; and that Mulcahy has become a feared loan shark from his prison cell.
In 2001, a television movie Witness of Truth: The Railway Murders was released, starring Huw Higginson and Nicholas Marchie as Duffy and Mulcahy, respectively.
Adler, Joanna R. Forensic Psychology: Concepts, Debates, and Practice. Willan Publishing, 2004. ISBN 1-84392-009-3
Harrower, Julie. Crime: Psychology in Practice. Oxford University Press, 2001. ISBN 0340844973
Wilson, Colin and Damon Wilson Written in Blood: A History of Forensic Detection. New York: Carroll & Graf Publishers, 2003. ISBN 0-7867-1266-X
John Duffy & David Mulcahy (3)
On February 5, 2001, British serial sex killer David Mulcahy was given three life sentences for murdering three women. He also received 24-year jail terms on each of seven counts of rape and 18 years each for five conspiracies to rape, to run concurrently. In short, Mulcahy, 41, was convicted after his childhood friend, John Duffy, spent 14 days in the witness box cataloguing their rape and murder scheme. According to Duffy during the 1980s the pair went on "hunting parties" searching for women. Duffy, who was known as the Railway Rapist because he used his knowledge of the rail network to target his victims, was caught and jailed for life in 1988. In custody he named his former friend -- who police suspected all along -- as his accomplice.
Their three confirmed victims were: Alison Day, 19, who was attacked close to Hackney Wick station in east London in December 1985; Maartje Tamboezer, 15, whose body was found near a station at Horsley, Surrey in April 1986; and Anne Lock, a 29-year-old secretary with a television company who was murdered near Brookmans Park railway station Hertfordshire in May 1986.
Mulcahy and Duffy were first interrogated by police in July 1985 about a series of rapes in North London. They were both released on bail and five months later they raped and murdered Alison Day in Hackney Wick, East London. In the spring of 1986 they raped and murdered two more women -- Maartje Tamboezer, 15, and Anne Lock, 29. The pair was rearrested in November of that year. Police charged Duffy with the three murders and six rapes, but had to release Mulcahy for lack of evidence.
In 1998 Duffy broke his silence and started talking about the murders and other rapes he had committed and implicated Mulcahy as his accomplice in many of the crimes. Mulcahy was finally arrested on February 3, 1999.
In court Duffy described how he and his best friend from childhood would hunt for victims throughout London. "We would have balaclavas and knives," John Duffy, 41, said. "We used to call it hunting. We did it as a bit of a joke. A bit of a game." Duffy, who was jailed for a minimum of 30 years in 1988 for murdering Alison Day, 19, and Maartje Tamboezer, 15, testified at the trial of Mulcahy that between 1982 and 1986 they hunted down and raped 15 women, killing three of them.
Police, believing the two are probably responsible for many more deaths, are re-investigating the 1980 murder of 19-year-old Jenny Ronaldson, who was sexually assaulted, strangled and thrown in the Thames. Detectives plan to examine a national file of over 180 unsolved murders of women to search for any links to Duffy and Mulcahy.
Exclusive: Railway rapist attacked by a tin of carrots in jail
By Justin Penrose - Sundaymirror.co.uk
Railway Rapist David Mulcahy needed 10 stitches after he was bludgeoned in jail... with a tin of carrots.
He was battered over the head by convicted robber Dean Winfield, who froze the can in a freezer before putting it in a sock to attack the serial killer in the showers.
Mulcahy - who murdered three women and attacked at least 12 more with accomplice John Duffy - has been left with a scar on his head.
The shower area was cordoned off and police scene-of-crime officers were called in.
Mulcahy, 50, is said to be furious and plans to press charges.
A prison source said: "There have been plenty of jokes flying around that Mulcahy's crack on the head is a 24-carat injury.
Winfield had clearly planned the attack and thought a can of carrots in a sock would be a suitable weapon.
"He managed to get Mulcahy in the showers but he only got a few blows in before the alarm was raised.
"Death by carrots wouldn't have been the most glamorous way to go, but it's nothing less than he deserves." Winfield, who is serving eight years for robbery, is on the same wing as Mulcahy at top-security Full Sutton Prison, near York.
Mulcahy and Duffy attacked and raped 15 women in North London between 1982 and 1986.
They were called the Thriller Killers and the Railway Rapists because they listened to Michael Jackson tapes as they roamed the streets looking for victims, many of them train commuters. A Prison Service spokesman said: "We can confirm an incident took place at Full Sutton where one prisoner attacked another.
"It was quickly dealt with and medical treatment given."
Life for 'depraved' killer
Friday, 2 February, 2001
A married father-of-four has been given three life sentences for carrying out a series of rapes and murders in the 1980s.
David Mulcahy was found guilty of the rape and murder of three women, seven more rapes and five counts of conspiracy to rape.
He planned the attacks with his childhood friend John Duffy - the so-called "railway rapist", who is serving life imprisonment for rape and murder.
Mulcahy had denied being Duffy's accomplice and continued to live a normal life with his wife and children in north London for 18 years.
Duffy, 41, who was jailed in 1988, named Mulcahy as his partner in 15 attacks.
The Old Bailey jury of six men and six women took five days to find Mulcahy guilty. He was sentenced to 24 years for the rape offences.
The Recorder of London Judge Michael Hyam said Mulcahy had "sunk to the depths of depravity" in committing the three murders.
Mulcahy, a 41-year-old builder from Chalk Farm, north London, had planned a number of the attacks in the 1980s with his "wicked soulmate", the jury heard.
Duffy and Mulcahy stalked women at suburban railway stations.
Giving evidence in Mulcahy's trial, Duffy said they had planned their 'hunts' meticulously, considering them "a bit of a game."
He told the court he became determined to bring his partner to justice, saying he could never forget attacks.
But Mulcahy challenged his childhood friend from the dock, claiming his innocence.
Detective Superintendent Andy Murphy of Hertfordshire police said Mulcahy's jailing meant an end to one of the most horrific series of rapes and murders the UK had ever seen.
"Today's verdict will ensure David Mulcahy will never be able to terrorise the streets of London again," he said.
"Our thoughts are with the victims of these crimes and those who have had the courage to give evidence in this trial."
The court heard how in July 1984 the pair raped two girls on Hampstead Heath.
He said the two men had laughed about the rapes afterwards while listening to Michael Jackson tapes.
In 1985, the pair turned to murder.
Alison Day, was just 19 years old when she was raped and strangled at Hackney Wick station, east London, in December 1985.
The following April, schoolgirl Maartje Tamboezer, 15, was attacked by the men as she went to the shops to buy sweets.
She too was raped and strangled near her home in Horsley, Surrey.
A month later in May 1986, newly-married LWT employee Anne Lock, 29, was killed by Mulcahy - probably suffocated - as she returned to her home at Brookmans Park, Hertfordshire.
'Lucky hunch' traps serial rapist
Friday, 2 February, 2001
A police officer involved in tracking down serial rapist David Mulcahy said it was a "lucky hunch" which set her on his trail.
Police had always suspected his involvement, but could not prove it.
Mulcahy was first interrogated with his friend John Duffy in July 1985 after the two were suspected of a series of rapes in north London.
But this was before the advent of DNA testing, and both were released on bail pending further enquiries.
Mulcahy was arrested, re-arrested and questioned in connection with the police investigation, but while Duffy was tried and convicted of murder and serial rape, Mulcahy was released to roam free for a further decade because of lack of evidence.
But in 1998, police got the breakthrough they needed when Detective Constable Caroline Murphy made a crucial discovery while checking if Duffy was still in jail.
She was told that while talking to a prison psychologist, Duffy had mentioned the involvement of a second man in the crimes, David Mulcahy.
This chance comment in 1998, prompted DC Murphy to consult forensic experts to see if modern science could be used to prove Mulcahy was culpable.
"It was just a hunch," she said.
After tracking down exhibits from years earlier, DC Murphy got a vital breakthrough, which proved her right.
A scientist contacted her to say that Mulcahy's DNA linked him, in a billion to one probability, to the rape of two Danish au pairs on Hampstead Heath in 1984.
DC Murphy said: "It was the best phone call of my life.
"They could hear me shouting down the corridor."
But police faced a dilemma over whether to make an instant arrest.
Had they done so, it would have put Mulcahy straight into the criminal justice system, with all its tight legal deadlines.
Detective Superintendent Andy Murphy, who was leading the inquiry, said: "While it may have been possible to sustain a charge of rape, there would have been no opportunity to gather evidence to charge him with the full list of offences for which he was believed responsible, including murder."
Mulcahy might have got a short sentence for the rape, and would soon have been free again.
They held back and took a gamble, deciding on a complete re-investigation.
Mulcahy was put under round-the-clock surveillance for two months, which involved 400 officers monitoring him, and every day reviewing the risk he posed to the public, particularly women.
Hundreds of witnesses - some living abroad - from the original inquiry were re-interviewed, and new witnesses were identified.
Duffy was re-interviewed in jail, but police admitted that handling him was complicated.
They had a sex killer serving a life sentence - which he knew meant the rest of his life - who was now to be a prosecution witness.
But Duffy's accounts proved accurate and reliable.
But if it had not been for DC Murphy's quick thinking, Mulcahy's reign of terror could have continued.
DS Murphy praised his colleague saying: "She had the foresight and professionalism to set the wheels in motion."
JOHN DUFFY AND DAVID MULCAHY: KILLING TO BE GOD
By Guy Toyn
David Mulchay was the dominant half of the 'Thriller Killers' - an evil sadist who felt 'Godlike' when he killed to demonstrate his power over women.
But he slipped through the net which snared John Duffy, even though detectives were sure he was the accomplice of the diminutive sex monster.
Duffy had been nailed by the size four footprints he left at the scenes of the horrific crimes and the distinctive twine he kept which had been used to bind murder victim Maartje Tamboezer's thumbs.
Despite six days of questioning and meticulous searches of his home, the Operation Hart team set up to track down the killers failed to find similar evidence to put Mulcahy in the dock with him.
Mulcahy had even arrogantly mocked officers when Duffy was jailed, threatening to sue the force for wrongful arrest. It was not until a third rapist began stalking Mulcahy and Duffy's favoured hunting grounds at Hampstead Heath, north London, that an extraordinary coincidence would lead to the solution of a case which had haunted those involved in the original inquiry.
And yet throughout an investigation spanning two decades the answer to the riddle was lying in a dusty British transport police store room at Euston station.
When suspicion began to centre on Duffy, the only realistic candidate as his partner in crime was Mulcahy, who was his only friend.
The rape victims had told of an uncanny, almost psychic understanding between the two men who must have known each other for years.
One said: 'They didn't tell eachother anything. It was two bodies but one brain.'
Another added: 'The two men seemed to be able to communicate without words - by nodding their heads.'
The pair had been almost joined at the hip since they met at in their first days at Haverstock Hill secondary school in North London. Mulcahy would later tell police his friend became 'almost part of the family.'
As they grew up together Mulcahy began to tower over Duffy physically and mentally, who never exceeded his schoolboy height of 5ft 4 inches and was referred to by Mulcahy as 'the midget.'
Both youngsters lived near Hampstead Heath and enjoyed 'spooking' the courting couples and homosexuals who gathered there.
They developed a love of the martial arts, spurred by the Kung Fu craze of the early 70's. Together they would relentlessly practice the powerlocks and holds which would later be so effective in trapping their victims.
OBSESSION WITH CRUELTY
They also began to share an obsession with the excitement they found in cruelty and crime.
Duffy's wife Margaret Mustafa told the Old Bailey how he would rape her during bondage sex sessions and terrorise their German Shepherd dog Toby.
Mulcahy would cheerfully tell the jury how he had bound a 12-year-old cousin hand and foot and tossed him into a bathful of ice cubes because the lad had difficulty getting out of bed. Mulcahy bellowed with laughter as he snapped photographs of the boy floundering in the melting ice.
In 1976 the pair were convicted of causing actual bodily harm when they shot four victims with an air rifle for fun. Shortly afterwards Mulcahy suggested they should rape a woman together.
Their 'wicked bond' was cemented by deep feelings of sexual inadequacy - Duffy's irrational hatred of women sprang from a low sperm count which prevented him from fathering children. Throughout his life Mulcahy had been troubled by difficulties in maintaining an erection which would drive him to escalating sexual depravity and violence in an attempt to arouse himself.
POWER OVER LIFE AND DEATH
'Duffy was the serial rapist. It was his partner who had that aggressive streak and the one who had the desire to dominate and exercise power and control over life and death,' said prosecutor Mark Dennis.
'Mulcahy was getting more out of this. He wanted something more than just rape. It was the taller man who enjoyed exercising power over their victims, tormenting them, humiliating them on occasions.
'Mulcahy was an arrogant and cruel character playing with his victims as if the whole thing was a game, getting satisfaction and enjoyment from bullying and picking on the vulnerable.'
According to Duffy, they plotted their first rape because Mulcahy hated the owner of a house in Hendon, north London, and wanted to sexually assault her to 'teach her a lesson.'
They broke in but the woman failed to come home. Another planned rape at a house in Notting Hill, west London failed when the woman returned home with a male friend.
In 1981 they escaped with suspended sentences at Alton Magistrates Court when they stole wines and spirits from a store room. Just over a year later the pair would carry out their first rape attack in a series of crimes which horrified Britain.
THE RAPIST'S KIT
The pair armed themselves with a 'rapist's kit' of balaclavas, knives and tape to gag and blindfold their victims.
Soon the Michael Jackson tape 'Thriller' would become another essential part of the kit.
'It seemed to motivate them as they drove, singing along, looking for victims,' Mr Dennis said. 'A substantial part of the thrill came from the anticipation of the hunt.'
Several of the rape victims remembered Mulcahy blaming them when he could not maintain his erection in attacks of increasing sadism. He would stroke the women's hair tenderly, kiss their neck and ask: 'Are you a virgin?' as he removed her clothes.
Running his knife across his victim's lips he whispering threats to gouge their eyes out or slice off their nipples and revelled in their pure terror.
'He was no longer satisfied by the sexual aspect, but by power, control, violence and torment,' Mr Dennis said. It was the desire for the ultimate thrill, the power over life or death that would cost three women their lives.
RAPED CLUTCHING A TEDDY BEAR
A 21-year-old who was walking home from a party in Kilburn in north west London clutching a teddy bear, was to become their first rape victim in October 1982.
Using sticking plaster to stifle her screams, they dragged her into a garden where she was stripped, blindfolded and raped. The victim recalled: 'I put my hands up and the taller man said: 'Don't worry, it is a knife.'
In March of the following year they targeted a 29-year-old restaurant manager who was walking near Finchley Road railway station. But the woman bit Mulcahy's hand and despite being kicked and punched she put up such a struggle they let her go.
An American social worker aged 32 was attacked on Barnes Common almost a year later on January 20, 1984. Mulcahy and Duffy, who were in the area decorating Duffy's parent's home, stripped and raped her.
Their fourth victim was a 23-year-old grabbed at West Hampstead railway station and dragged across the tracks on June 3 of that year. She told the court: 'They had a knife and said they would cut me if I didn't do as I was told. All I could say was: ''Please don't hurt me.” They laughed as they passed the distraught woman afterwards in their getaway car, joking that they should offer her a lift.
GAGGED WITH TAPE
A girl of 22 was gagged with tape after she was seized on Highgate West Hill a month later on July 8. Fortunately the rapists fled when a neighbour called the police. When the girl was comforted she still had pieces of tape on her wrists, one of which would provide crucial evidence against Mulcahy.
A week later on July 15 two 18-year-old Danish au pairs were attacked on Hampstead Heath as they walked arm in arm laughing together. One said: 'He told me to take off all my clothes and lie down. Then he pulled his trousers down to his knees and lay on top of me.'
Three months later the pair were arrested when they were stopped in Mulcahy's Talbot Horizon with stolen building materials. A black balaclava was found in the car but the pair escaped with fines after Mulcahy told police he used the mask when he was working as a plasterer on dusty ceilings.
On January 26, 1985 they attacked a 20-year-old German au-pair under a canal bridge at Brent Cross. Her scarf was used as a gag and blindfold as she was bundled towards the nearby bridge.
'The man without the knife sat down and undressed me. He was not rough but he stripped me naked,' she said. Once fluent in English, the woman has refused to ever speak or read the language again or tell her husband of the ordeal.
By January 30 the pair were back trawling Hampstead Heath where they selected a 16-year-old virgin. Duffy told the court Mulcahy was becoming so violent he broke off the attack fearing his friend would kill the girl.
On February 2 they tried again with a French au-pair who was also grabbed near the Heath but the attack was aborted when she screamed and struggled.
Duffy claimed he stopped another attack on a 23-year-old the following month because he was again worried about Mulcahy's behaviour when the victim was dragged to a flats near the Heath.
Desperate for another victim, the pair selected a 25-year-old solicitor's clerk on March 1 and raped her on a bench on the Heath. By now the sexual excitement on the hunt was not enough for Mulcahy, who was having more and more difficulty becoming aroused.
MEETING BY THE RIVER
Four days after Christmas 1985 they targeted Alison Day, who had been due to meet her fiance at his printing firm in Hackney Wick.
The 19-year-old near was snatched at Hackney Wick railway station and dragged to snow covered playing fields nearby.
After both men had raped Alison, she tried to escape and fell or was pushed by Mulcahy into the freezing water of a feeder canal. Duffy claimed he pulled her out, and Mulcahy was so excited by the incident he raped her again, then tore off a piece of her blouse to throttle her.
He recalled: 'She was saying things like ''It is only his moustache I have seen, I won't tell anyone, please don't hurt me.'' I was watching David and the girl. The next thing I noticed was he was putting some material round her neck and starting to twist it.'
Mulcahy later told his accomplice he had killed Alison because she might recognise them. But Duffy said: 'David actually enjoyed it, saying it gave him power - the decision over life and death. I remember him going on: ''It is God-like - having the decision over life and death.'''
COAT WEIGHED DOWN WITH STONES
Alison's sheepskin coat was weighed down with stones and she was hurled back into the water. She was found 17 days later, bound and gagged with her hands tied behind her back.
On April 17, 1986, 15-year-old Dutch schoolgirl Maartje Tamboezer was knocked off her bicycle with a length of fishing line stretched across the path - a technique Duffy had learnt from one of his favourite books, The Anarchist's Cookbook.
The teenager was marched across the fields between Effingham and East Horsley in Surrey and raped by Duffy, who claimed Mulcahy suddenly lost his temper.
'He was becoming very aggressive - hyper, shouting at the girl,' Duffy recalled. 'He then raised his fists and hit the girl. She crumpled to the floor. She was struck on the head, at the side. It was a swinging blow. I noticed he had a rock in his hand, or a stone. She just crumpled up and fell on the floor. I believe she was unconscious.'
GARROTTED WITH HER OWN BELT
Former altar boy Duffy said Mulcahy then ripped off Maartje's belt and looped it around her throat, telling him: 'I did the last one, you'll do this one. He passed me the belt. It had a piece of stick through it which was twisted and he gave it to me in my hand,' Duffy told the jury.
'I actually started twisting it while David turned away. I think I just got caught up in it. It is very difficult to explain. I just continued twisting until she was dead.'
Duffy said they both left the scene but Mulcahy returned and set Maartje's body alight, stuffing burning tissues into her vagina hoping to destroy forensic evidence.
Newly wed TV secretary Anne Lock, 29, still had the suntan from a dream honeymoon scuba diving off the Seychelles when she was ambushed getting off a train at Brookmans Park, Hertfordshire on May 18, 1986. When the pair spotted her bicycle in the station's shed they hid in the bushes and waited until she returned.
Duffy said he raped Anne, then Mulcahy threw him the a bunch a keys and he went to collect the car. He told the court: 'David said he had taken care of it. He was very evasive, like he was playing mind games. He was saying: ''She won't identify us now''. He was very excitable, buzzing. He was even saying: ''Keep your eyes open for another one.'''
Anne's decomposed body was found two months after she was murdered in undergrowth just a mile from her home. She had been suffocated with her own sock.
Ten years after the murder of Anne Lock, with Duffy safely behind bars Mulcahy must have believed he would never be caught. But on August 6 of 1996 another rapist sprang from the undergrowth in near Hampstead Heath, sparking a chain of events which would lead to Mulcahy joining his friend behind bars.
Ted Biggs, then 34, was a salesman at a bedding shop in Hitchin, Herts, leading the double life of a rapist by night. He attacked 66-year-old woman on the Heath that summer's night and struck again in Hampstead in September 1998.
Police launched Operation Loudwater to track down Biggs, who would prey on six victims before he was jailed for life. By sheer chance one of the officers on Operation Loudwater, DC Caroline Murphy met DC John Haye in a pub. DC Haye had been the exhibits officer in the Duffy inquiry.
They quickly realised the two cases had striking similarities in location, and the knife and the balaclavas that were used.
THE NET CLOSES
DC Murphy called Whitehouse prison in Cambridge to make sure Duffy had not been let out on day release and could not be responsible for the offences. She learned Duffy was in fact being interviewed by psychologist Jenny Cutler, who told her Duffy had given the name of his accomplice as David Mulcahy.
All the surviving exhibits from the original case were re-examined and tested using DNA techniques which were not available in the 1980s. Samples taken from the clothes of one of the au-pairs Mulcahy raped on Hampstead Heath showed there was only a one in a billion chance he was not the attacker.
Senior officers then found than in an astonishing blunder a piece of tape used to bind the woman attacked on Highgate Hill West had not been tested for fingerprints before it was consigned to the storeroom at Euston station. Their worst fears were realised when four experts confirmed the fingerprint they found on the tape belonged to David Mulcahy.
Tragically, Mulcahy and Duffy could have been stopped after just three rapes.
Mulcahy was convicted of three murders, seven rapes and five charges of conspiracy to rape after a trial lasting more than five months. The jury of six men and six women had deliberated for 19 hours and 42 minutes over four days.
Duffy was convicted of two murders, five rapes, and another sexual assault but cleared of Anne's murder at his trial. He later confessed to another nine rapes - including that of Anne Lock - six conspiracies to rape and two burglaries with intent to rape.
Described by the judge who sentenced him in 1988 as 'a predatory animal' Duffy is now thought to be one of Britain's most prolific rapists with up to 50 victims.
At the end of Mulcahy's trial in February 2001 The late Recorder of London Judge Michael Hyam told him: 'These were acts of desolating wickedness in which you descended to the depths of depravity in carrying the them out.' Duffy and Mulcahy will never be released.