ITV‘s new crime drama Until I Kill You has captured the attention of viewers with its chilling tale of one woman’s horrifying ordeal at the hands of her boyfriend.
But it is perhaps even more terrifying because it is based on the true story of agency nurse Delia Balmer’s near fatal relationship with axe murderer John Sweeney.
Branded the ‘scalp hunter killer’, Sweeney murdered and dismembered two former girlfriends before dumping their remains in canals in Rotterdam and London.
He attempted to murder Delia, bludgeoning her with an axe, but she remains his sole known survivor and is currently serving life for his crimes.
The series is inspired by the 2017 memoir, Living with a Serial Killer, and is accompanied by a new documentary which details the true timeline of events.
In the drama, romance blossomed between Sweeney (played by Shaun Evans) and Delia (played by Anna Maxwell Martin) when he approached her at a bar in Camden, London, one evening and offered to buy her a drink. They bond over their shared love of travel.
While at first appearing attentive and caring, buying Delia bouquets of flowers and showing outward signs of affection, their relationship quickly deteriorated.
Sweeney, who took up residence in Delia’s flat, became erratic and controlling towards Delia, criticising her appearance and where she spent her free time.
When she finally gathered the strength to demand him to leave, she was met with his wrath.
Delia Balmer (pictured) who survived a horrific ordeal at the hands of her ex-boyfriend John Sweeney
Delia (pictured as a young woman) met Sweeney in a pub in Camden, London, when she was working as an agency nurse
‘Scalp Hunter’ John Sweeney, was jailed for life for murdering Melissa Halstead and Paula Fields and throwing their mutilated bodies into canals
Anna Maxwell Martin as Delia Balmer and Shaun Evans as John Sweeney in ITV’s Until I Kill You
Delia found herself increasingly tormented by Sweeney. She was hacked to within an inch of her life by the killer, who attacked her with a hammer and an axe.
Prior to the attempt on her life, Sweeney had held her captive and repeatedly raped her in a week-long ordeal, for which he was arrested but released on bail.
In 1994, in a terrifying ordeal spanning just a few days, Sweeney held Delia against her will, tied her to the bed and intimidated her with threats of disfiguring her tongue.
It is then that Sweeney admitted to murdering his ex-girlfriend Melissa Halstead, 33, in Rotterdam.
In her memoir, Delia recounted Sweeney’s admission: ‘We had a room in Amsterdam. I went in. There were two Germans there with her. I killed them all. I didn’t know what to do with the bodies. I sat with them for three days. On the third day, I cut them up, and I put them in bags and I threw them in the canal.’
However, Delia’s struggles did not end there, as she was then let down by the police and the legal system.
Her life was then put in danger once again when Sweeney was released on bail and made a second attempt on her life.
He was finally caught in 2001 and sentenced to nine years in prison for his attack on Delia.
Sweeney’s first victim Melissa Halstead met a recently divorced Sweeney in 1986 while she was working internationally as a model and photographer.
About a year into their relationship, he had been charged at least once for domestic violence against her, and was subjected to a number of fines until the pair relocated to Austria.
He had tracked her down, stalked her, tied her up and attacked her with a hammer which cracked her skull.
After being released and ordered to leave Austria, the pair settled in Amsterdam, The Netherlands.
But her body was found floating in a canal in May 3, 1990, after he transported her body to Rotterdam.
Detectives found deeply disturbing drawings by the murderer, including sketches that suggested how he butchered Melissa.
The American model’s body was found dismembered in a Dutch canal. In one poem, Sweeney said she had been ‘fed to the fishes and chopped into bits, Amsterdam was the pits’.
There were also self-portraits captioned ‘seal hunter’ in which the killer was shown as a devil with a bloody axe.
It was not until 2008 that Melissa’s remains were identified using an advanced DNA test, paving the way for Sweeney to be charged with her murder.
The new documentary revealed how Sweeney butchered the women’s bodies, removing their heads and hands so their corpses couldn’t be identified.
He then tied up their body parts with rope and put them into bags filled with tiles and bricks to weigh them down in the water.
Melissa was thrown into a Rotterdam canal, while Paula’s was put into London’s Regent’s Canal.
The body of Paula Fields, a 31-year-old mother was cut into six pieces and stuffed into holdalls.
The Halewood woman’s head, hands and feet were never found.
Prosecutors during the killer’s trial in 2011 said this was a deliberate attempt to prevent them from being identified and Sweeney being exposed as being responsible for the murders.
While at first appearing attentive and caring, buying Delia bouquets of flowers and showing outward signs of affection, their relationship quickly deteriorates (pictured is Anna Maxwell Martin as Delia Balmer and Shaun Evans as John Sweeney)
Anna Maxwell Martin as Delia Balmer in Until I Kill You which dramatises the relationship between Delia and axe murderer John Sweeney
Delia, who collaborated on the ITV production of Until I Kill You, said she remains an ‘angry person’ as a result of her experiences
While serving time for the assault on Delia, Sweeney was interrogated about Melissa and Paula. Thanks to advancements in DNA technology, as well as Delia’s testimony, authorities were able to bring a case against him.
Sweeney was given a whole life sentence at the Old Bailey in 2011 after being convicted of murdering Melissa, a former model from Ohio, and Paula Fields, a mother-of-three living in north London. The woman’s remains were found a decade apart.
In 2023, it was reported that Sweeney had been linked to some of the cases included in an Interpol appeal which is seeking to uncover the names of 22 women – each of whom are suspected murder victims from across Europe since 1976.
Three of those pictured by Operation Identify Me were women who were decapitated and had their remains left in canals in the Netherlands.
Sweeney worked in the country in the 1990s, and his victim Melissa, was found there.
Sweeney declined to leave his cell at Belmarsh prison when his sentence was pronounced.
Judge Mr Justice Saunders, who presided over the sentencing, told the court: ‘These were terrible, wicked crimes. The heads of the victims having been removed, it is impossible to be certain how they were killed.
‘The mutilation of the bodies is a serious aggravating feature of the murders.’
Delia, who collaborated on the ITV production of Until I Kill You, said she remains an ‘angry person’ as a result of her experiences.
In an interview before the show was released she said: ‘My concern has always been to get the truth out by whatever means. I remain an angry person.
‘Sweeney was let out on bail. The police gave me insufficient protection before his final assault. Later, I was forced to go to court to be further traumatised by the system.’
Who is serial axe monster ‘Scalp Hunter’ John Sweeney?
Former carpenter John Sweeney, 66, was once regarded as one of the most dangerous men in Britain.
He was sentenced to a whole life tariff in 2011 for butchering two girlfriends and dumping their remains in city canals.
The Merseyside-born killer was found guilt of the murder of US model Melissa Halstead, whose remains were found in a Rotterdam canal in 1990.
Over 30 years after his first gruesome crime, her missing head and hands have still never been found.
A decade later, he killed mum-of-three Paula Fields, 31, in London.
Melissa Halstead, a 33-year-old American model and former girlfriend of Sweeney’s, whose remains were found in a canal in Rotterdam in May 1990
Sweeney also murdered Paula Fields, a mother of three from Liverpool
Sweeney was tracked down by police in 2001, and was then convicted of the attempted murder of another girlfriend, Delia Balmer, in 1994
He cut her body up and dumped her remains in the Regent’s Canal.
Sweeney was tracked down by police in 2001, and was then convicted of the attempted murder of another girlfriend, Delia Balmer, in 1994.
During their three years together during the nineties – shortly after he killed Ms Halstead – Ms Balmer faced a campaign of violence from Sweeney.
Just before Christmas in 1994, he attacked Ms Balmer with an axe, leaving her with stab wounds and without her left little finger.
By the time police arrived Sweeney had fled.
He spent years on the run before he was eventually brought to justice for the two murders and attempted murder.
The evil killer earnt his morbid nickname from the vile sketches he drew of him attacking his victims.