Original subtitles

-In February 1988, 29-year-old carpenter John Duffy

was on trial for rape and the murder of three women.

He was one half of a terrifying duo

who had become infamous across London.

The newspapers had dubbed them the "Railway Killers."

-As one victim later said,

"They were like two bodies with one brain."

They knew exactly what the other one was going to do.

Their bond was unique and wicked.

-After receiving six life sentences,

Duffy still refused to give up the name of his accomplice,

a 29-year-old father of four named David Mulcahy.

-I think Mulcahy is somebody who returns to a normal life

and has absolutely no problem in doing that.

He didn't feel bad about what he's done,

and it's very much about self-preservation for him.

-But over a decade later,

Mulcahy was still free and Duffy had had enough.

He finally confessed to all his crimes and told investigators

he would testify against his former friend.

-It was almost as if he considered

this was an act of betrayal to what was a unique

and wicked bond for decades.

These were so poles apart now across the courtroom.

-John Duffy and David Mulcahy had made their mark

as two of Britain's most evil killers.

♪♪

♪♪

♪♪

Two rapists struck fear into the hearts of women across London.

When John Duffy was arrested in November 1986,

it brought an end to an horrific 4-year crime spree

across the British capital.

But it would be another 15 years before Duffy's accomplice,

David Mulcahy,

was found guilty for his part in the heinous crimes.

Between them, the deadly duo were responsible

for over 20 rapes and three murders.

It was Duffy's testimony at Mulcahy's trial in the year 2000

that helped to incarcerate his one-time friend.

-As the judge delivered the sentence,

Mulcahy gave no reaction, staring straight ahead.

The judge told him, "These were sadistic killings,

and of the two of you, I have no doubt it was you

who derived gratification from the act of killing."

-One of the lead detectives charged

with catching the so-called Railway Killers

was Charlie Farquhar.

His son Simon remembers the case well.

-These women had their lives disfigured by these two men.

Three women lost their lives to these two men.

Nothing can ever atone for that,

and it's a pretty grim thing to immerse yourself in

for a period of time.

-Over 30 years after the murders,

Simon has penned a book

about the hunt and capture of Duffy and Mulcahy.

-Once I started to really delve into it

and really investigate it,

I realized I was completely unprepared

for just how horrific a case like this actually is.

Unlike police officers, you have all kinds

of defenses built up over years

and years to deal with these sort of things.

I did wander into this as a bit of an innocent,

and it does still really haunt me.

-The story of these two killers begins half a century ago.

John Duffy was born in 1958 and David Mulcahy in 1959

on separate sides of the Irish Sea.

-Well, both Duffy and Mulcahy are from Catholic families,

Irish-Catholic families.

Duffy was actually born in the Republic of Ireland

and came over to England with his family

when his father was looking for work.

Mulcahy was born in England, and he was the son of a man

who went on to become a pub landlord.

-In 1970, the two 11-year-old boys struck up a friendship

while attending Haverstock School in north London.

-I think that Duffy and Mulcahy came together

for a variety of different reasons.

They were both from Irish families,

and the Irish community were still suffering

quite a lot of discrimination at this point in time

in British society.

Also, there was a sense in which they could be a partnership

because Duffy, he was quite short.

He had red hair. He was bullied at school.

But Mulcahy was bigger.

He was broader, and he could be his protector, essentially,

so it was quite a brotherhood

really rather than any kind of casual friendship,

and it was them against the rest of the world.

-By the age of 13,

both boys were already displaying

signs of disturbing behavior.

-Well, Mulcahy was suspended from school

after he and Duffy were found essentially

playing a version of cricket but using a live hedgehog,

and they were found after they had been engaging in this,

and Duffy was covered in blood, and he was laughing at Mulcahy,

who was also covered in blood,

so this really is quite a warning signal.

It's basically a complete lack of empathy

for the feelings of this living creature

that they were tormenting,

and they're starting to experiment here.

Their behavior is starting to escalate,

and it really is quite a significant red flag.

-They became fascinated with each other's company.

They would haunt Hampstead Heath wearing Halloween masks

and jump out and frighten courting couples

who used to meet on Hampstead Heath, terrify them.

And they took enormous pleasure from it.

-So these two,

they're really having the time of their lives doing this.

They're really enjoying having that power over others,

but I think to come across them out there

in the park in the dark would have been really,

really frightening.

-As the two teenagers became young men,

Duffy and Mulcahy's scare tactics took a criminal turn.

-So in their case, you started with the pranks

and moved on to burglary and car theft.

They stole the cars, and they didn't steal the car

because they want to sell the car.

It wasn't for profit.

They stole the car because they wanted to drive around,

and they wanted have fun.

-But then we see that escalate.

We see that their physical violence angle kind of start

to come out a little bit more,

so we hear stories of them shooting at people

in the streets with an air pistol.

-The pair found work at Westminster City Council,

Duffy as a carpenter and Mulcahy as a plumber.

On one job, Mulcahy had spotted a woman

who he thought needed to be taught a lesson.

He and Duffy went to her house after dark intent

on raping the woman.

-So Duffy and Mulcahy break into the house

and lay in wait for the woman

whose house Mulcahy has been decorating,

but the woman, thankfully, doesn't come home that night.

She's gone to a friend's.

This infuriates both Duffy and Mulcahy.

-So you've got a plan developing here.

They're starting to actually decide,

"Well, this is what we're going to do."

This isn't something that's opportunistic.

This is something that's very much premeditated.

-Duffy and Mulcahy were undeterred.

They tried the same plan again with a different woman

but escaped from her house when she returned home with a man.

-And they're probably talking about, "Say, look, the same old

breaking into people's house and waiting for them is no good

because we don't know if they're going to come back.

We don't know if they're going to come back with somebody else.

So instead of that, how about we actually drive around,

find someone, see someone on the street,

and then we pounce on them

on a dark alley or something like that?"

So I think the rush that they got from breaking into the house

just motivated them to go and do the real thing.

-By 1980, both men were in their early 20s and married,

but their lust for rape remained.

Two years later, they were ready to strike.

-In October 1982, they found the first one, 21-year-old girl

coming back from a party carrying a teddy bear.

They put a knife to her throat

and forced her into a garden of an empty house.

They said -- I think it was Duffy who said,

"Don't worry. We only want the teddy bear."

Nothing could have been further from the truth.

They stripped the girl, gagged her, blindfolded her

and raped her.

-From then on, the attacks became incredibly prolific.

At one point, there was three in one night.

They would generally drive around together

listening to music to psyche themselves up.

They carried with them kits of balaclavas, or masks.

Mulcahy would put gaffer tape inside his jacket,

which would then be used to gag the victims.

They'd often blindfold them, as well.

-Paul Cheston, from the Evening Standardnewspaper,

recalls the fear felt across the capital.

-That added to the sense of terror felt by Londoners

that it was almost a military-style operation,

and the planning that was going into it

was much more than just spurred attack, moment attacks.

-Mulcahy would always ask the victims their names

and addresses as well

and would often steal items which had their address

on it, library cards, that sort of thing.

The idea was that if these victims went to the police,

"We will find you," you know, and so on.

They always made sure their victims were reduced

to a state of abject terror.

-One such attack occurred in the summer of 1984.

-The attack on the two Danish au pairs

took place in July 1984.

That night, Duffy and Mulcahy had been driving around

for a long time unable to find a victim,

and finally they saw these two 18-year-old girls

walking along Spaniards Road on the edge of Hampstead Heath.

They had been out in the West End

and missed the last train home and were walking back.

They decided to attack them both.

Duffy had a replica gun.

Mulcahy had a knife.

They were dragged off the road and onto the Heath and brutally,

brutally assaulted.

-For 3 years, Duffy and Mulcahy continued undetected.

-In late 1985,

the police connected 24 attacks on women in north London,

and posters went up across London

for the north London rapists.

They knew they were looking for two men,

a shorter man and a taller one.

They didn't know a great deal about the taller man,

but they knew that the shorter man was

an A-secretor blood group, had fair hair.

The taller man, they knew a lot less about.

He had a darker complexion.

He had a mole on his chin.

He had mousy brown hair, was about 5-foot-11 tall

and was much more violent than the shorter man.

-The majority of the attacks had taken place

in the vicinity of train stations.

The press had dubbed them the "Railway Rapists."

-It was a very big story in London

that was a widespread concern

not just because rapists were loose

but because they were finding victims

in and around railway stations, and London is --

Millions of Londoners travel on public transport,

and it was a serious, serious concern for Londoners.

-But it was about to get worse.

Their next victim would not just be raped.

She would be murdered.

By December 1985, John Duffy and David Mulcahy

had been sexually assaulting women

in and around railway stations in London for over 3 years.

Still undetected by the police, their confidence was growing.

-I think it was inevitable

that this was only going to escalate further

because we've got two men here

who are really enjoying the sexual violence

that they've been perpetrating,

and often when you look at offenders

who are engaged in this kind of behavior,

they're not going to just stop at a particular level.

They want to keep upping the ante,

so I think murder was unfortunately inevitable here.

-On December the 29th, 1985,

Alison Day caught a train to Hackney Wick station

to meet her fiancé.

-Alison Day was a 19-year-old secretary

who lived in Upminster with her parents.

She had been adopted as a baby and brought into a very,

very loving household.

She worked as a secretary in a local solicitor's office.

She was enormously bubbly and popular,

and she had just got engaged.

-But Alison never completed her journey.

-At that time, obviously it was a torture

for her parents not knowing if she'd just run away,

although it seemed absolutely,

you know, implausible that she had.

What had actually happened was that she'd got the train

to Hackney Wick,

and Duffy and Mulcahy were waiting for her on the platform.

They could quite easily have walked her out of the station,

but instead they decided to walk her across the live rail tracks

down the railway siding and then under the railway bridge.

There, they both committed horrific attacks on her.

And at this point, as far as Duffy was aware,

the plan was to leave Alison on the far side of the bridge

and them make their escape,

but Mulcahy wanted to do something more than that,

so he made her walk along the outside ledge of the bridge.

She couldn't swim.

It was also 1 degree below freezing,

and she fell into the River Lea

screaming out that she couldn't swim.

She waded to the edge, and Duffy helped her out,

and then she managed to run.

She ran for her life, and this enraged Mulcahy.

And Mulcahy yelled out, "Get the bitch, John. Get her."

-Duffy caught up with Alison,

but Mulcahy's slip of the tongue had sealed her fate.

-He said to Duffy, "We have to do this because she's seen us,

and she knows your name now."

-He cuts up the blouse she's wearing

and uses it to strangle her.

And he says to Duffy, "You turn the tourniquet one more time

just so that we're in it together."

-Alison was begging and pleading for her life,

and her last words were,

"Please, it's only the mustache I've seen.

I won't tell anyone. Do not hurt me."

It's just unbelievable.

She was strangled, rolled into the river,

and then they both drove back.

Duffy was panicking.

Mulcahy said, "We would have been done

for attempted murder anyway. It's got to be --

That's just the way it is."

He dropped Duffy off.

Mulcahy picked his children up, went back home,

and Alison Day was dead.

-The 19-year-old's body was found 3 weeks later

face-down in a canal.

The Railway Rapists had become the Railway Killers.

Duffy and Mulcahy had strangled Alison to death

using a tourniquet.

-I think when we're looking at the murder of Alison Day,

and we hear about them twisting the tourniquet together,

basically what they're doing here is saying,

"We're in this together. We've both done this.

You can't blame it on me. I can't blame it on you."

So there is that pact going back to their school days

when they said they're not going to grass on each other.

That really is the kind of cementing of that.

-Less than 6 months later, Duffy and Mulcahy struck again.

This time, their victim was even younger.

-Maartje Tamboezer was a Dutch schoolgirl.

She had just celebrated her 15th birthday.

On Thursday, the 17th of April, at 4:00 in the afternoon

after coming home from school,

she had something to eat, had a drink,

and then got on a bike to cycle into the village

to buy some sweets from the shop.

Her mum said to her, as she always did,

"Don't take the railway path

because it's very quiet along there.

Take the long way around."

Maartje, being a teenage girl, thought, "It'll be all right,"

and she took the railway path, and Duffy and Mulcahy

were waiting at the end of it for her.

-Maartje was raped by both men

in the woods near Horsley station.

Mulcahy used a rock to knock

the 15-year-old schoolgirl unconscious

and then made the decision that she had to die.

-He then instructs Duffy that he has to kill her.

"After all, I killed the first one.

You've got to kill the second one."

They take her belt, put it around her neck,

and they stick a stick through the belt

to tighten the pressure on her neck.

And they do indeed kill the poor 15-year-old, innocent,

had done nothing more than ride her bicycle,

and she had done nothing to these two men.

It was an absolutely abhorrent, depraved, disgraceful crime.

-Once Duffy had killed Maartje Tamboezer,

Mulcahy ran up to him and says,

"Well-done. You've done good,"

almost like he was the captain of a football team

congratulating a new player.

He then told Duffy to go back to the station

and said he would see him there.

He said he wanted to go back to the body

to make sure there were no fingerprints left on the rock.

He actually went back to make sure that she was dead

and to make a pretty vile attempt

to destroy any forensic evidence

there was by setting fire to her.

-Maartje's body was found in the woods the following day.

-The sight that greeted those police officers

was absolutely horrific.

She had been savagely raped,

submitted to brutal head injuries,

strangled, and the body had been set on fire

in a clear attempt to destroy forensic evidence.

She was lying beside some bluebells,

and the police christened the inquiry

Operation Bluebell in tribute to her.

-Metropolitan Police Detective Charlie Farquhar,

who was investigating the murder of Alison Day,

contacted his colleagues in Surrey Police.

He believed the two murders were connected.

-And when he told Surrey on the phone,

Surrey realized that the piece of wood

that was lying next to Maartje's body

wasn't in fact just a piece of wood on the ground.

It had actually fallen out of the knots in the rope,

and obviously it was the same murder method.

And at that point, this became a joint-murder inquiry.

Shortly afterwards, the connection was made

with the London rapes,

and this went from being a small inquiry

being run from a portacabin to the biggest criminal manhunt

since the search of the Yorkshire River.

-Duffy and Mulcahy didn't wait long

to claim their third victim.

On May the 18th, 1986, recently married Anne Locke

boarded a train from Brookmans Park station in Hertfordshire,

but she never made it home.

-Anne Locke was 29 years old.

She was a bright, attractive girl

with a huge amount of talent and future in broadcasting.

She was a secretary at London Weekend Television,

and she was in love.

She had been married just 4 weeks earlier

and returned from a dream honeymoon in the Seychelles,

had gone scuba diving.

She still had a suntan from that lovely holiday,

and she disappeared.

-Paul Dockley from the Hertfordshire Police

led the inquiry into Anne's disappearance.

-The weirdest thing was that the initial officers

attending this missing-person inquiry

discovered that her bike was missing,

and in fact we found it behind the shed

leaned up against a tree,

which was unusual to say the least.

And so we started searching.

We started searching around the railway station.

We also did a trawl of people that may have been on the train

coming out of London on that particular night.

-It was the latest twist in a story

that had captivated the British public.

-The disappearance of Anne Locke

was a media sensation that summer.

The "Missing Bride Story," as it was called.

-And the headlines about Missing Bride escalated.

The speculation became more forensic

about what could have happened to her.

They were already piecing her disappearance

to the two previous murders,

and there was a tangible air of, you know,

"What are the police doing? They cannot even find a body

let alone find the people responsible."

-But the police had little to go on.

They could not even be sure

that Anne had reached Brookmans Park station.

-The first time that the police genuinely realized

that Anne was probably dead

was when Inspector Paul Dockley was searching the area,

and even though the search was massive,

the search was generally at ground level,

and being a good detective, he looked up,

and up in the trees, cradled in the branches, was Anne's diary.

-I didn't know it was Anne's diary immediately,

but I saw it in the tree, so we recovered that.

And within the next day,

we reasserted our search in the area

and recovered her purse,

her LWT pass and her address book.

So at that point,

which was probably 4 weeks into the inquiry,

we knew at that point that Anne had returned to Brookmans Park.

-And just a week later,

the police found out the devastating truth

of what had happened to 29-year-old Anne.

-Eventually, after 9 weeks, the search was called off.

The police had gone to the edge of the Hertfordshire boundary

and still couldn't find anything.

And then a few days later, some railway workers found her body

just into the Metropolitan Police District

dreadfully decomposed.

-Following the discovery of Anne Locke's body,

we actually developed a joint investigation

with Hertfordshire, The Met, Surrey,

and British Transport Police.

Investigating a murder is almost like starting a jigsaw puzzle

with a piece of blue sky because you do not know

the pattern of how things have occurred.

You're faced with a scene, but it doesn't actually tell you

necessarily who the offender is,

so you're working through that jigsaw of trying to put together

all the elements in order to prove a case.

And it's hard as a detective to detach yourself

from what you actually see.

You're dealing with this on a regular basis, and, well,

I don't think I've ever come across a case like this.

-As one victim later said,

"They were like two bodies with one brain."

They knew exactly what the other one was going to do.

They split up and ran in different directions.

They knew where they were going to meet up and so on.

Their bond was unique and wicked.

-While police from three regions searched for them,

Duffy and Mulcahy remained hidden in plain sight,

married men with regular jobs,

but the net was closing in on the pair.

In the summer of 1986, Hertfordshire,

Surrey, and London's Metropolitan Police forces

were working together to try and capture

the two men the papers were calling the Railway Killers,

but the evidence they had was minimal.

-So this was the 1980s.

Forensic science was still in its infancy

compared to the advances that have been made since.

Also, it wasn't just forensic science

which was in quite a primitive state at the time.

Also, police treatment of sexual crimes

wasn't as sophisticated or as understanding as it is now.

-The surviving victims had provided

investigators with descriptions of their attackers.

They knew that one of the rapists was tall and violent,

the other short with piercing blue eyes.

Forensic evidence suggested that the shorter man

had the blood group A.

-We were literally going through a list of people

that could be possible offenders called the Zed Men.

And the Zed Men had been previously arrested.

And you got to remember this is pre-DNA,

so we're the precursor to DNA,

and we were looking at A-secretors,

so people who secreted in their blood

or their saliva or semen an A-secretor factor.

-The Zed Men had over 2,000 people in it.

John Duffy was on it because of a serious assault

on his wife the previous year.

He was number 1,595 on that list,

and it was just a case of working through the list

and interviewing every single one of those men.

Eventually, number 1,595 came up,

and it was time for him to be questioned.

He sat down.

He was quite polite and cooperative

but was behaving rather strangely.

He was trying to be much too helpful,

and his answers were rather glib.

The two police officers interviewing him

had an uneasy feeling.

They left the room and said to each other,

"This could be him,"

not least because of these piercing blue eyes he had,

which many of the rape victims had commented on the shorter man

having great, piercing blue eyes.

-Despite their suspicions, Duffy was released,

but before long, he was back.

-The two investigators rang me and said,

"Governor, you won't believe this."

He said, "Last night, John Duffy presented himself

at West Hampstead Police Station.

He'd been slashed across the chest with a blade,

and he was saying that he had amnesia.

I took him to his home address.

He didn't recognize his mom, his dad, his dog, nothing."

And he was taken to Friern Barnet Hospital,

where he was sectioned.

-The investigation had taken a bizarre twist.

Duffy was still a suspect,

but the police were not permitted to talk to him

while he was sectioned.

-So Duffy was at Friern Barnet Hospital,

and we weren't allowed to interview him

for at least 8 weeks, and unbeknown to us,

we thought he was in a secure unit at Friern Barnet Hospital.

In actual fact, he was allowed to come and go.

-Duffy had been attacking on his own since mid-1984,

and unlike Mulcahy,

didn't possess the same level of self-control.

He was becoming wildly unstable,

and he also took a lot more risks

when he was carrying out these attacks

and was much more careless.

-And, unfortunately, he went out to a railway line

and raped a young girl

whilst he was in the care of Friern Barnet Hospital.

-The last attack he committed

when he knew the police were closing in on him

was on a 14-year-old schoolgirl in Watford,

and during that attack, her blindfold slipped,

and she saw him very clearly.

When Duffy was arrested, that girl walked into the I.D. parade

and walked straight up and pointed him out,

and at that point, that was the end for John Duffy.

-He said nothing.

He said "No comment" to everything.

He didn't deny anything.

He just said, "No comment."

And he would talk to me about martial arts as long as the day.

You know, he was quite happy to talk about that,

but anything to do with rape,

missing girls, murders, not interested.

And, of course, his answer was,

"I've been in hospital. I've had amnesia.

I don't remember anything.

I don't remember anything before going into hospital."

-Detectives knew they needed some solid evidence

if they were going to charge Duffy with murder,

and the string that he and Mulcahy had used to tie up

Maartje Tamboezer 7 months earlier

was about to give them just that.

-They used a particular piece of string

that was called somyarn,

and a lot of us will think string is string is string,

but when you get down to the forensic detail,

how it's made, what it's made of,

all of these things can be very different,

and if you happen to use a very unusual piece of string,

it's going to help identify where that's come from.

-And the company said, "This is a very unusual piece of string

because it's been taken from the end of the yarn,

so basically it's on a loom, and it's cut,

and this is an end piece."

And they said to us, "If you can find the ball of string,

we could do a match."

So the search team who went to Duffy's parents' address

searched the outside toilet,

and in a bucket in there was a ball of somyarn.

-It was enough to finally put an end to the murderous career

of one of the Railway Killers.

-Gradually, the evidence is building up against Duffy,

and he was charged with the murder of Anne Locke

in addition to the murder of Alison Day

and Maartje Tamboezer and a number of rapes.

-Investigators were certain that Duffy's accomplice

was his oldest friend, David Mulcahy.

-He was actually arrested four times over the next few months.

Every time that police got another break,

they brought him in again

but eventually realized there just wasn't enough evidence.

There was no forensic evidence to connect him

with the crimes at all.

When they searched these vehicles,

they found in the cab of his van masking tape,

balaclavas, all sorts of things that incriminated him,

but none of it was enough.

-But his name was known to the press,

and a lot of people, a lot of pressmen,

went to see him to see

just to gauge what sort of reaction he would give.

Of course, there was no reaction.

He would say, "No comment,"

and he got increasingly angry about what he called harassment,

but the press knew that there were two people involved

in the Railway Rapist cases,

and Duffy's friend was the prime suspect.

-John Duffy would go to trial alone,

and there was more bad news for investigators.

The judge instructed the jury

to dismiss the murder charge of Anne Locke

due to a lack of evidence.

-This caused a lot of anguish with Anne Locke's family

and was a surprise amongst the press,

but the problem was that in the Locke case

there was no surviving victim to give any evidence.

There were no witnesses to the attack,

the fact that the body had laid unfound for 2 months,

that there was no DNA evidence.

-In February 1988, John Duffy's trial

began at the Old Bailey in London.

-John Duffy walked into the witness box

at the Old Bailey

and put up one of the worst defenses ever heard

by an Old Bailey jury.

To suggest that he was suffering from amnesia

and could remember nothing about what happened during the period

in which he was accused of the murders and rapes

was frankly an insult to the intelligence of anyone in court,

let alone the jury.

His whole body language was of defiance.

"I am going to give you nothing.

I am standing here sticking to my story, and I don't care."

And the piercing eyes that his victims spoke of, the wild,

staring blue eyes,

absolutely radiated out from the witness box across the court.

-Duffy was found guilty of two murders and five rapes.

He was given six life sentences, but despite everything,

he refused to give up the name

of his accomplice and best friend.

-Well, maybe the reason

why Duffy kept quiet right at the beginning,

they had their agreement that they had from a very young age,

and they never broke that agreement,

"We're never going to rat on each other."

So when he went to prison, he probably decided,

"I'm going to stay true because I am, you know, a good friend,

or I am the man I am, whatever, I was true to my word."

-As Duffy's sentence began,

David Mulcahy remained a free man.

The man and father of four set up his own decorating business,

and life went on as normal.

-I think Mulcahy is somebody who returns to a normal life

and has absolutely no problem in doing that,

and that's because he can switch.

He can flip very easily

because he doesn't feel empathy for his victims.

He doesn't feel bad about what he's done,

and it's very much about self-preservation for him.

-Everybody knew that David Mulcahy

was the second man,

but he honestly thought that he got away with that,

and for the next 10 years he pretty much had.

-But as Duffy's time in prison passed by,

something inside of him clicked.

After claiming to be suffering from amnesia,

he suddenly got his memory back.

By 1999, he was ready to talk and tell the police

all about his accomplice, David Mulcahy.

11 years after his conviction, John Duffy was in prison

serving six life sentences for his part

in a series of rapes and murders in and around London

between 1982 and 1986,

but Duffy's partner in crime, David Mulcahy, remained free.

-Mulcahy was one who first suggested,

"Let's break into the girl's house."

He was the one who first suggested,

"Let's go and find victims on the street,"

and he was the one who first suggested,

"Let's commit murder,"

but the one who was paying all the price was Duffy,

so it's very, very easy for you to see that after 10 years,

you know, the little fuse from Duffy got to an end,

and he was like, "Forget it. I'm going to come clean."

-In 1997, Duffy, who had originally claimed

to be suffering from amnesia about the crimes,

had begun visiting a prison psychologist.

-So basically Duffy had been in prison for 10 years and thought,

"This is an opportunity to talk and talk and talk,"

and basically he told the psychologist

about the offenses he had committed

and the fact that he hadn't committed them alone.

-During their conversations, Duffy reveals that he committed

these crimes with another person,

and she casually asked which prison his codefendant is in.

And Duffy drops the bombshell.

"He's not in prison. He was never caught."

She says, "I have to tell the police about this,"

which Duffy agrees to.

And so she tells the police, "John Duffy has just named

his accomplice.

It's someone called David Mulcahy."

-It was a big breakthrough for detectives who had been trying

to bring Mulcahy to justice for over a decade,

and a huge slice of fortune was about to initiate his downfall.

-There's an extraordinary coincidence here.

At the same time that this was going on,

a similar series of attacks was taking place on Hampstead Heath,

and police began to suspect

that David Mulcahy may have become active again.

They had a DNA profile for the attacker.

Mulcahy was brought in, questioned.

They took his DNA, and it didn't match.

And once again, he left the police station very cocky,

very arrogant.

-But the police now had Mulcahy's DNA on file.

They had to go back 15 years to find a match.

-Amazingly, in deep storage,

was the clothing of the Danish au pairs' rapes

on Hampstead Heath in 1984,

and when the clothing was run through forensics,

one sample of clothing had Duffy's DNA on it,

and the other had David Mulcahy's DNA.

And suddenly, after all those years of thinking

he got away with it,

suddenly that case had come back to haunt him.

-On February the 6th, 1999,

David Mulcahy was taken into custody.

He would never be free again.

-As soon as I found out that the police had arrested

and charged a new suspect in the Railway Rapist cases,

I, like every other pressman

who had been in any sort of involvement in the case,

immediately knew that it had to be David Mulcahy.

-He thought that they were just clutching at straws.

He thought that this was just another attempt to arrest him

which was going to fall through.

When they sat down to question him,

the first thing they asked him was about the night

of the 15th of July 1984 in the company of John Duffy,

and he wasn't expecting that at all.

And then the police revealed that they'd found his DNA

on an exhibit from that crime,

and the odds of it being another person other than him

were one in one billion,

at which point a police officer held up the wastepaper basket

because he was violently sick,

and he realized that the game was up.

-Mulcahy's trial was set for October 2000,

and the prosecution had a surprise witness lined up.

John Duffy was ready to testify against his former friend.

He had admitted to detectives that the pair had killed

all three women, including Anne Locke.

-Duffy couldn't be retried for the murder of Anne Locke

because at that time they were still enforcing

something called the double-jeopardy rule,

which means you can't be tried for the same crime twice.

It's a silly law, which is now gone,

but Duffy said himself at the time,

"If I could be tried again for this one, I would be."

So there was never any point where he was trying

to minimize his involvement.

-After it seemed like he was going to get away with murder,

the gathered press were excited to finally see Mulcahy on trial.

Paul Cheston was in the courtroom throughout.

-The Mulcahy trial was unquestionably the trial

of the year at the Old Bailey.

There was huge anticipation at reopening

this historic case dating back almost 15 years,

and, as always,

when the case opens and the defendant is brought in,

everyone's eyes just immediately shift straight to the dock.

He looked more like a bank manager than a serial killer,

and he immediately set about getting an air of relaxed

as if this was just maybe a formality

that would be thrown out of court straight away.

-On November the 6th, 2000,

John Duffy entered the courtroom to give evidence

against his former friend and accomplice.

-There was huge anticipation, a real frisson in court

when John Duffy shuffled in through the judge's entrance,

not through the main entrance

because he was a category A prisoner,

the first category A prisoner, serving life, murderer,

to give evidence for the crown at the Old Bailey.

And when he entered court, he shuffled.

He had his head down. He would mumble.

The piercing eyes were hooded.

He didn't want to look up.

-The tension in the courtroom

between the two killers was palpable.

Duffy avoided eye contact with Mulcahy.

-It was almost as if he considered

this was an act of betrayal,

and he couldn't look in that direction.

He didn't want to catch Mulcahy's eye.

Meanwhile, Mulcahy in the dock

was acting as if he'd never met him,

and this was some complete stranger.

And he was scribbling notes on this and that,

and this seemed bizarre for what was a unique

and wicked bond for decades.

These were so poles apart now across the courtroom.

-True to his word, Duffy gave a detailed account

of the duo's career of rape and murder.

-His accounts, particularly of Alison Day

pleading for mercy with Mulcahy claiming,

"We're going to have to kill her because she's seen us,"

and Alison Day saying,

"I've only seen a mustache, and don't do this to me.

Don't hurt me. I won't tell anybody,"

and Mulcahy,action in Duffy's words,

twisting the tourniquet and throttling her to death,

that for the first and only time,

John Duffy showed a glimmer of remorse.

His eyes welled up, and his voice faltered.

The judge called a halt.

He was led away, and the case was adjourned

for 10 to 15 minutes.

-Duffy gave testimony across 2 weeks

of the 5-month murder trial.

On February the 2nd, 2001, the jury had made a decision

on the fate of David Mulcahy.

-And when the jury forum was asked to go through

on each count on this long indictment

and answered the first,

"So did you find Mulcahy guilty or not guilty?",

answered, "Guilty," there was such an escape of emotion

and, like, steam from a kettle of relief,

and then it went through the indictment,

"Guilty. Guilty. Guilty. Guilty. Guilty."

-And when it came to the verdict on Anne Locke,

because this had been a case of Duffy

had been found not guilty of because of the lack of evidence,

this was finally the chance to really lay this to rest.

And when a "Guilty" came in on that as well,

the atmosphere was extraordinary in that court.

-And there was a lot of victims, a lot of victims' families,

in court, an inevitable outbreak of relief, of tears.

Mulcahy himself seemed entirely unmoved.

It's almost as if he expected it,

and it was an extraordinary scene at the Old Bailey,

even by the Old Bailey standards.

-And David Mulcahy had nothing else,

no other way of hurting those victims anymore,

so as he walked out of the dock, he looked over

at two of the victims sitting in the public gallery

and smirked at them.

It was his last desperate act of revenge, and then that was it.

And then he was promptly sentenced to a total of

258 years in prison,

so I think we can safely say he's never going to get out.

-Sentencing Judge Michael Hyam told Mulcahy,

"There were acts of desolating wickedness.

You descended to the depths of depravity."

-Finally, 15 years after the murder of Anne Locke,

John Duffy and David Mulcahy were both behind bars.

12 years were added to Duffy's sentence

while Mulcahy has still never confessed to any of the crimes.

-I think the fact that Mulcahy has always maintained

his innocence

really is a testament to his narcissism.

He is protecting the image of himself

that he's putting out there to other people.

He doesn't want others to believe that he is

this individual who has carried out these heinous crimes.

-There's always been speculation that Duffy

and Mulcahy were guilty of other rapes,

several of which will not even have been reported,

but thank goodness at least, finally,

they were brought to justice.

-These were perhaps crimes that they may not have committed

had they never met, but they come together,

and you create the perfect storm.

-For 4 years, John Duffy and David Mulcahy

targeted vulnerable women in and around London.

They callously raped over 20 and murdered three,

one of them a 15-year-old schoolgirl.

Although initially detained in 1986,

it wasn't until Duffy broke the bond

that he and Mulcahy have shared since their childhood

that their world of lies fell apart and justice

was finally served upon the twisted pair

known as the Railway Killers.

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