A confession: how dna was key to just one halliwell murder conviction

A CONFESSION: MARTIN FREEMAN STARS IN THRILLING NEW CRIME DRAMA Halliwell killed Becky Godden-Edwards, 21, back in 2003 and buried her in a shallow grave in a field. In 2011, he kidnapped

and murdered Sian O’Callaghan, 22, triggering an investigation into her disappearance. Despite admitting to both murders, Halliwell’s confessions were ruled “inadmissible” in court, so the

forensic evidence had to be rock solid. RELATED ARTICLES He would eventually be linked to Sian’s murder by DNA evidence on her body as well as blood in his car. In 2012, he was sentenced to

life in prison, with a minimum of 25 years. However, because Becky’s body was retrieved so many years after her death, there was no usable DNA evidence so police had to investigate elsewhere

to prove he killed her. Over the course of the next few years, police painstakingly traced Becky’s last movements and matched them with where Halliwell had been at the time. READ MORE: A

CONFESSION: HOW CHRISTOPHER HALLIWELL MAINTAINS HIS INNOCENCE Halliwell was linked to Sian's murder through DNA evidence (Image: PA/ Wiltshire Police) Becky Godden-Edwards was murdered

in 2003 (Image: PA/ Wiltshire Police) They also found soil on tools in his shed matching samples in the field where Becky was buried. In 2016, Becky’s family finally saw justice for her

murder as Halliwell was sentenced to a whole life order, meaning he will never be released from prison. When Sian first went missing in 2011, Halliwell was soon a suspect, because automatic

number plate recognition technology placed him at the scene of her disappearance.  However, instead of arresting him he was put under surveillance in the hope that he would lead detectives

to where he was keeping Sian. Martin Freeman as DS Steve Fulcher and Joe Absolom as Christopher Halliwell in ITV's A Confession (Image: GETTY) RELATED ARTICLES After five days he was

deemed a suicide risk and arrested but Detective Superintendant Steve Fulcher was still sure Sian could still be alive. Instead of following police protocol and taking Halliwell back to the

police station and allowing him access to a solicitor, he took him to the spot where Sian had disappeared and asked him where he had taken the young woman. Eventually, Halliwell admitted he

had killed Sian and agreed to take the detective to where he had buried her. Then, he revealed that there was a second victim and took DS Fulcher to Becky’s burial sight. DON'T MISS A

CONFESSION: HALLIWELL'S DAILY ROUTINE INSIDE CATEGORY A PRISON [EXCLUSIVE] A CONFESSION: WHAT EVIDENCE PINNED BECKY’S MURDER ON HALLIWELL? [ANAYLSIS] A CONFESSION: HOW CHRISTOPHER

HALLIWELL ‘LAUGHED AT GUILTY VERDICT' [REVEALED] Press conference scene from ITV's A Confession (Image: ITV) Flowers left outside club where Sian O'Callaghan was last seen

alive (Image: GETTY) However, as DS Fulcher had breached the Police and Criminal Evidence Act, Halliwell’s confessions were not able to be used in his prosecution. This is when the DNA

evidence became such a key part of the investigation. Catching Britain’s Killers on BBC Two at 9pm tonight will look into the first murder case that used DNA fingerprinting.  It will look

into how it lead to the conviction of Colin Pitchfork, who had raped and murdered two 15-year-old girls in Leicestershire named Dawn Ashworth and Lynda Mann. A CONFESSION: CHRISTOPHER ADMITS

TO ANOTHER MURDER In 1985, Sir Alec Jeffrey at Leicester University found a way of identifying an individual’s genetic code from blood or semen. Police were able to link a semen sample from

Lynda’s body to a person with type A blood and an enzyme profile that matched only 10 percent of males. This first exonerated their initial suspect Richard Buckland and proved the girls

were killed by the same man. Then, they asked around 5,000 local men to provide blood to be tested. After it was discovered Pitchfork had asked a colleague to go in his place, he was brought

in and tested again and found to be a match. Colin Pitchfork was caught with DNA evidence (Image: Leicestershire Police / Getty) This was the first conviction of this kind and started a

whole new line of investigation for detectives on murder and rape cases.  The BBC documentary will also explore how the development and evolution of this investigative tool led to

convictions for other crimes that had, until then, been impossible to solve. The revolutionary science was picked up by police forces in the US, Australia, New Zealand, Austria, Germany and

Slovenia for contemporary investigations.  It was also used to solve countless cold case and bring killers to justice decades after their crime.  Within a few years, police forces all over

the world were creating huge databases of genetic profiles.