In the Footsteps of Killers: Could the unsolved Milk Carton Kids case be the work of a ‘serial killer’ paedophile?

"I JUST put the tie round his neck and just tightened it," Brian Field said of the moment he murdered a 14-year-old schoolboy in his car after raping him.

"He just sort of convulsed a bit, sort of gasping for air, and I just carried on – and suddenly he went lifeless."

Killer paedophile Field choked the life out of his first victim, Roy Tutill, in Surrey in 1968 – a crime which would go unsolved for over 30 years.

It was only when Field, now 85, was arrested for drunk driving in 1999 that cops matched his DNA with a sample from Tutill's clothing.

That was just one in a string of horrific sex crimes Field committed against young boys over several decades, with other offences including abduction and sexual assaults.

Now a new Channel 4 documentary series asks if Field could have been responsible for other high profile crimes involving children – including the Milk Carton Kids case.

In the Footsteps of Killers shows Silent Witness star Emilia Fox and criminologist Professor David Wilson hunt for answers.

By the end of their search, Wilson gives a chilling assessment of their findings.

He says: "We could be uncovering one of the worst serial killers of children this country has ever known."

'I'll never get over it'

On the night of Boxing Day, 1996, two young boys were seen alive for the last time at a petrol station in Chelmsley Wood, West Mids.

The worried families of David Spencer, 13, and 11-year-old Patrick 'Paddy' Warren phoned the police later that evening when they realised both children were missing.

Patrick's red Apollo bicycle, which he'd been given as a Christmas present the day before, was later found at the back of the petrol station.

An employee of the petrol station bought the boys a packet of biscuits and then watched them leave that night – but she says she didn't hear shouting or fighting before they vanished.

Despite the prized bike being left behind, cops told the boys' families they believed the "streetwise" boys had probably just run away and would come home when they were hungry.

But agonising months went by without any word from the boys.

The young friends were dubbed the "Milk Carton Kids" after pictures of David and Patrick were printed on milk cartons in hundreds of Iceland stores in a public appeal for help launched by the National Missing Persons Helpline in April 1997.

It was hoped the publicity tactic, which had previously been used to help solve cases in the US, would generate new leads – but no major breakthroughs came.

To this day, the boys' bodies have never been found, and no one has been charged with their murder.

"I’ll never get over it. Never," David's mum Christine says in the documentary.

"I want closure of this. I want my son home so I can put him to rest."

Child killer snared

The case went cold for years until paedophile Brian Field was arrested for Roy Tutill's rape and murder.

Field, a gardener who lived off the radar, had picked up Tutill as the boy was coming home from school in Surrey in 1968.

Field raped and murdered Tutill in his car, keeping the schoolboy's body in the boot for days before dumping him in woodland.

A DNA swab from a drunk driving arrest decades later proved Field's guilt, and he was sentenced to life for the killing in 2001.

As well as the 1968 rape and murder of Tutill, Field was also convicted of five other sex offences against teenage boys.

In the 1980s, he'd also attempted to abduct two teenage boys in Oswestry, Shrops.

The boys managed to escape his moving car after Field picked them up and ordered them to strip.

Field was given four years for the highly unusual double kidnapping.

"I don’t know of any other offender who’s ever been convicted of attempting to abduct two teenagers at the same time," Prof Wilson says.

At the time of Mark and David's disappearance in 1996, Field was living near their homes and was a known regular in local pubs.

Schoolboy murder mystery

The Milk Carton Kids mystery isn't the only unsolved case Field has been linked with.

In 1984, Mark Billington was just 15 years old when he disappeared from his Birmingham home.

Ten weeks later, his lifeless body was found in woodlands seven miles from the family house.

An initial inquest into his death ruled an open verdict – but his family believed he was murdered.

"When the police said that Mark had killed himself, nobody believed it," heartbroken mum Winifred says in the documentary.

One junior officer on Mark's case, Bob Poole, also believed foul play was involved in Mark's death.

He paid for a Swiss knot expert to analyse a rope found with Mark's body, and the expert concluded the knot used was too sophisticated to have been made by a child.

In 2002, a new inquest ruled Mark was murdered.

Poole, who has since passed away, also told the Billingtons about Brian Field, who'd lived less than two miles from the family.

When Field was convicted of Tutill's murder using DNA evidence in the early 2000s, Mark's family hoped they might finally find out what happened to their teenage boy.

But in the years since Mark's death, important items of evidence relating to his case including the rope and his clothes, have gone missing.

"It’s documented that they searched for them," Mark's sister Cheryl Jeyes says of the police.

"But because Mark’s case was never officially recorded as a crime, they didn’t have to then keep the artefacts."

To this day, Mark's murder remains unsolved – but the Billingtons believe Field was responsible.

In one email to Mark's dad, Poole also revealed that he was trying to speak to two "reluctant witnesses" in Chelmsley Wood in relation to the Milk Carton Kids case.

The investigator wrote that one of the witnesses "saw Field with both lads a few days before they disappeared".

Prof Wilson thinks that could explain a crucial mystery in Dave and Patrick's disappearance.

"If the boys knew Field prior to Boxing Day night when they disappear, that’s why nobody hears anybody scream or shout or fight as they’re being abducted," he says.

Prime suspect

Criminologist Graham Hill is also convinced Field is the most likely suspect in the Milk Carton Kids' disappearance.

Predatory paedophile expert Dr Hill has interviewed Field on several occasions after his conviction for Tutill's murder.

"If I had a drink, I’d get that urge that I want to have sex," Field told Dr Hill in one interview.

"And that’s when my trouble started. I just lost my head or something."

In one conversation in recent years, Hill spoke with Field on behalf of West Midlands Police about the Milk Carton Kids case.

"There were some tantalising little bits of information that he gave up," Dr Hill says.

I have never seen a suspect that is better for the abduction of those two boys than Brian Field

Dr Graham Hill

"He never admitted that he abducted those boys. But I think we got to the stage – certainly West Midlands Police got to the stage – where they could put him, the night in question, in the vicinity of where the two boys went missing.

"And that he’d been drinking that night, and he was in a white van."

Hill added: "In my view, I have never seen a suspect that is better for the abduction of those two boys than Brian Field."

Field, who declined to speak with the makers of In the Footsteps of Killers, has always denied any involvement in David and Patrick's disappearance.

West Midlands Police said they began a missing persons investigation as soon as the boys were reported missing and they completed a large number of enquiries to try and find them.

This included following up enquiries as a result of media campaigns, where CCTV existed this was recovered and viewed and friends of the boys were traced and spoken to.

This missing person investigation was overseen by an Inspector and in February 1997 was then progressed by CID.

West Midlands Police say there is currently insufficient evidence to charge Brian Field with the disappearance and murder of David and Patrick.

The case remains open and subject to regular review and any new evidence will be investigated.

The Mark Billington case remains an open murder investigation and West Midlands Police say it would be inappropriate to comment on individual suspects.

In the Footsteps of Killers is on Channel 4 tonight at 10pm and will be available on catch-up