What are the real-life events behind ITV's true crime drama A Confession?

Here's what happened:

The disappearance of Sian O'Callaghan

In the early hours of Saturday 19th March 2011, a 22-year-old named Sian O'Callaghan left Suju's nightclub in Swindon after a night out with her friends. It should have been less than a 15-minute walk home to the house she shared with her boyfriend Kevin Reape (played by Charlie Cooper).

However, she never returned.

Realising something was seriously wrong when Sian failed to come home or answer his texts, Kevin raised the alarm. At 9.45am he called the police to report that his girlfriend had gone missing.

How did the police find Sian?

Sian was caught on CCTV at 2.52am leaving the nightclub in Swindon, Wiltshire.

The next important clue came from a text message sent by Kevin at 3.24am, which was received on Sian's phone; analysis showed that her mobile phone had been in the Savernake Forest area at the time the message arrived. This was roughly 12 miles away.

If she had traveled 12 miles in just half an hour, that meant the journey from Swindon Old Town could only have been made in a vehicle. But who was driving the vehicle? And where had they gone next?

The case attracted widespread attention and press coverage, and on Tuesday 22nd March around 400 members of the public were allowed to help the police search the forest. But the following day, there were "significant lines of inquiry" – and the public were asked to stand down from the search.

How did the police track down the killer?

The senior investigating officer on the case was Detective Superintendent Steve Fulcher (played in A Confession by Martin Freeman) – and the events of 24th March would be the defining moment of his career.

On that day, the police made an urgent appeal for witnesses who had spotted a green Toyota Avensis with taxi markings. The car had been seen on CCTV pulling up next to Sian on her way home.

Away from the press, Fulcher and his team had also identified the taxi driver – 47-year-old father-of-three Christopher Halliwell (played by Joe Absolom) – and were keeping him under surveillance, hoping he would lead them to Sian.

But on that same afternoon, Halliwell was observed buying a large quantity of pills. Fearing he was planning to overdose, the police swooped in and arrested him in an Asda car park in north Swindon, charging him with the kidnap (not murder) of Sian. They also seized his green Toyota Avensis.

The murder of Becky Godden-Edwards

A young woman called Becky Godden-Edwards had gone missing a number of years before, last seen in 2002 or 2003. She was a drug addict and sex worker, and after she disappeared her mother Karen Edwards (played by Imelda Staunton) had spent years hoping she would return.

After his arrest, Halliwell revealed the location of Sian's body. She was found in a shallow grave near Uffington in Oxfordshire, stabbed in the head and strangled.

But he also made another confession – offering to lead Fulcher to a second body. Human remains were uncovered at a field in Gloucestershire, and they turned out to belong to Becky. She too had been strangled.

Did Steve Fulcher break the rules to get Halliwell's confession?

After Halliwell's arrest, Detective Superintendent Steve Fulcher made an unusual decision – with huge ramifications.

Instead of bringing Halliwell back to Gablecross police station in Swindon where he would have had access to a solicitor, Fulcher ordered his officers to take Halliwell to a nearby Iron Age hill fort called Barbury Castle.

At this point, Fulcher still hoped to find Sian alive. He wanted to seize the opportunity to grill Halliwell – before it was too late.

Fulcher himself spent hours questioning Halliwell at Barbury Castle, breaking down his defences and sharing his cigarettes and forming a connection. Finally, Halliwell confessed to Sian's murder and offered to take him to Sian's body, leading the police to her burial spot.

And then, out of the blue, the taxi driver said: "Do you want another one?"

Ultimately, Halliwell confessed to two murders to Fulcher and led the police to the bodies of both Sian and Becky.

But to get those confessions, Fulcher was accused of breaching the guidelines of the Police and Criminal Evidence Act (PACE) by failing to caution Halliwell and denying him access to a solicitor at the time the confessions were obtained.

A judge then ruled that Halliwell's confessions to killing both victims were actually inadmissible as evidence in court.

So while Halliwell was charged and convicted of the murder of Sian O'Callaghan (the case was strong enough without that confession), at this point he could not be tried for the murder of Becky Godden-Edwards.

The fallout for Steve Fulcher was huge. In September 2013, the Independent Police Complaints Commission (IPCC) found that Fulcher had a case to answer for "gross misconduct" for breaches of PACE and for ignoring force orders. He was found guilty in January 2014 and given a final written warning by a disciplinary tribunal.

In May 2014, Fulcher resigned from Wiltshire Police. He still believes he made the right decisions on that day.

“It’s a simple moral issue,” he told the Guardian. “I did these things because they were the right things to do in these circumstances. In fact, they were the only things to do.”

Was Christopher Halliwell found guilty of Sian's murder?

In May 2012 Christopher Halliwell pleaded not guilty to the charge of murdering Sian O'Callaghan, but when he appeared in Bristol Crown Court in October 2012 he pleaded guilty to her murder.

He was sentenced to life imprisonment with a minimum tariff of 25 years.

Was Christopher Halliwell found guilty of Becky's murder?

Halliwell was not charged with Becky's murder in his 2012 trial, as a judge had ruled his confession to the crime was inadmissible in court.

However, four years later judge Sir John Griffith Williams decided that Fulcher's evidence could – and should – be heard in court as part of the case. He argued that the original judge (Mrs Justice Cox) had been correct in her ruling, but that since Halliwell had "unequivocally" pleaded guilty to Sian's murder, the concerns over PACE were "no longer relevant."

The judge ruled: "I am satisfied that the evidence of the conviction of the defendant of the murder of Sian O'Callaghan is admissible to prove the defendant's propensity to commit murder.

"I am satisfied also that the defendant's confession to the murder of Becky Godden and his taking the police to where he had buried her was not the consequence of oppression."

A murder trial began, and in 2016, after two hours of deliberation, a jury found Christopher Halliwell guilty of the murder of Becky Godden-Edwards.

He was sentenced to life imprisonment with a whole life order, meaning he will not be eligible for parole and is unlikely to ever be released from prison.

What happened to Steve Fulcher? Where is he now?

This investigation damaged Fulcher's career as a senior police officer, and despite keeping his job with a final written warning in January 2014, he resigned from the force in May of that year.

Since then, the Christopher Halliwell case has remained at the centre of his life. He published a book, titled Catching a Serial Killer: My hunt for murderer Christopher Halliwell, and has also spoken many times in the press about his experience of the case. With his name so closely associated with the story he has found it hard to branch out, though in 2017 he was working for a private company in Mogadishu, Somalia.

In 2018 he appeared on the ITV show To Catch a Serial Killer with Trevor McDonald.
“My view is that I have brought two daughters back to their mothers and I’ve prevented other victims resulting from Halliwell’s continued pursuit of his career as a serial killer," Fulcher told McDonald.

“But for my course of action Becky would still be in that field, Sian would never be found and Christopher Halliwell would be walking the streets.”

Fulcher has broadly received the support of the victims' families.

"I for one stand by Fulcher's steadfast resolve to try and find my sister Sian," Liam O'Callaghan said.

Did Christopher Halliwell murder any other girls? Was he a serial killer?

"I deliberately and very carefully didn't get into specifics of other victims," writer Jeff Pope said.

Halliwell is thought to have killed Becky in 2003, while Sian was killed in 2011. It is possible that there were other victims before or after Becky – but he has never been charged or convicted of any other murders.

In 2014, the police found "up to 60" items of women's clothing buried in woodland, close to where a pair of Sian's boots had been found. Detective Chief Inspector Sean Memory said there could be an "innocent explanation" but pointed out: "Someone has made some effort to hide it."

And speaking after Halliwell's sentencing in 2016, Memory said: “I’m very very clear that there must be other victims out there whether they are sexual offences or other women that he has taken. The offending behaviour for Becky was cold and calculated. I cannot believe that was his first offence from being a burglar in the 1980s to a murderer in 2003. There is a significant gap in his offending. Sian wasn’t murdered until 2011. What happened in the interim eight years?"

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"Generally, we echo Fulcher's belief that there are other victims," Pope said, explaining the drama's approach to the question. "He killed Becky in 2003, he killed Sian in 2011, so that's eight years.

"But we certainly don't get into any of the specifics of those other cases that have been attached – there are other murders up and down the country that are now attached to Halliwell, and we absolutely scrupulously did not get into any of that."

Why? "Because you don't want to mention a name and then give a family false hope. If we mention one of those names a family might think, 'oh, I wonder if...' So we very carefully say, 'We believe there are other victims,' and leave it at that."

A Confession will air on ITV in September 2019