Who is Christopher Halliwell, is the A Confession killer still alive and how many people did he kill?
IT HAS been years since Claudia Lawrence went missing from York - but double killer Chris Halliwell has only ever been "linked" with the case.
The cabbie was already serving life for the murder of Sian O’Callaghan in 2011 when he was finally brought to justice for killing Becky Godden in 2003.
Who is Christopher Halliwell and is he still alive?
Taxi driver and former burglar Christopher Halliwell, 52, lived with his partner Heather Widdowson and her three daughters in a suburban semi in Swindon.
Brian Jerome who lived nearby said at the time of his arrest: "He's a really nice guy. He'd always have a smile and he'd often be out working on his car.
"I couldn't believe it when I heard. Nice man, nice family, nice girls."
Halliwell is a father of three children himself with ex-wife Lisa.
Fellow minicab driver Neil Barnett said: "Real nice bloke, a genuine bloke, a normal run-of-the-mill bloke. I've got two daughters I would have trusted them in his car."
But the respectable family man had a darker side and was regularly using prostitutes.
Hookers who were picked up by Halliwell in the weeks before Sian’s death said he got "rough and weird" with them, and some got frightened and called for help.
Police say he had a brutal childhood and has "issues" with women.
Detectives fear he may have killed many more victims after he boasted he wanted to be a serial killer like his idol Myra Hindley.
Halliwell has been linked to a string of women who went missing in his home town.
The cop who nailed him for killing Sian has also linked Halliwell to the disappearance of Claudia Lawrence in York - where his father lived close by - in 2009.
How many people did he kill?
A secret trophy store of 60 items of women’s clothing suggests dozens more victims than the two he was put away for may have been raped or killed by him.
Only two of the items have ever been identified – a cardigan worn by Becky, who disappeared in Swindon in 2003.
Halliwell was locked away for life for the killings of Sian O'Callaghan and Becky Godden.
Personal assistant Sian O’Callaghan, 22, was abducted by Halliwell as she made her way home from a night out in Swindon in the early hours of March 19, 2011.
Halliwell was arrested five days later after CCTV showed Sian getting in his green Toyota Avensis taxi outside a nightclub.
He confessed to killing her and took police to her body.
The depraved killer was jailed for life for her murder.
Sian's mum Eliane Pickford has revealed she "always thought" her daughter's killer was involved in more murders.
Prostitute Becky disappeared from Swindon in 2003.
After he was arrested for killing Sian, Halliwell offered detectives "another one" and led them to where he had buried her headless corpse eight years earlier.
He told officers he was a “sick f***er” and asked: “Is it too late to get help?”
He then said: “I know you aren’t a psychologist but what the f***’s wrong? Normal people don’t go round killing.”
Despite initially denying Becky's murder, Halliwell admitted taking a girl from Swindon between 2003 and 2005, when he "had sex with her and then strangled her".
But even after confessing he was able to dodge justice for Becky’s killing on a technicality.
Senior investigating officer Steve Fulcher was found not to have followed procedures on the treatment of suspects, meaning Halliwell’s confession was inadmissible in court.
Eventually new evidence was uncovered, allowing police to bring the killer cabbie back in for questioning over Becky’s murder.
Evidence from a former prostitute who said Halliwell was “besotted” with Becky, and forensic evidence linking his shovel to the field where she was buried, were enough to send Halliwell down at the second attempt.
A judge slammed his “cock and bull” defence as he passed a whole life tariff - reserved for the most dangerous criminals such as serial killers.
Officers who dealt with Halliwell believe he may have killed other victims besides Sian and Becky.
Melanie Hall, 25, disappeared after leaving a nightclub in Bath in 1996. Her body was found by the M5 in 2009.
Halliwell reportedly once told a colleague at his minicab firm: “Who knows what or who you will find buried out there, there could be loads of people over the years.”
Another potential victim is prostitute Sally Ann John, 24, who vanished from Swindon in 1995. She and Halliwell lived on the same street at the time.
Tina Pryer, 39, Thi Hai Nguyen, 20, and Sandra Brewin, 21, have also been missing for years.
And Linda Razzell, 41, disappeared in the Wiltshire town in 2002.
Her husband Glyn has spent 13 years in jail for her murder but maintains he is innocent.
It has emerged Halliwell was obsessed with Linda after doing building work at the Razzells' home four years before she was killed.
Incredibly, the date Linda went missing in 2002 — March 19 — links Halliwell, his second known victim Sian and another unsolved case.
Is ITV's A Confession accurate?
Following on the success of Manhunt, A Confession is another crime drama which deals with a real-life case. It airs every Monday.
It tells the story of 22-year-old Sian O’Callaghan who went missing in Swindon in 2011 after leaving a nightclub to walk to her boyfriend's house.
Senior Investigating Officer Steve Fulcher is in charge of handling the case and firmly believes that Sian is still alive.
In the end he links Sian's case to the disappearance of Becky Godden-Edwards and breaches police procedure to ensure that justice prevails.