ITV’s gripping new crime drama, Until I Kill You, has captivated audiences with its chilling portrayal of violence, obsession, and survival.
Inspired by real events, the series follows the harrowing experiences of agency nurse Delia Balmer, who survived a brutal assault by her then-boyfriend, the notorious “scalp hunter killer” John Sweeney. This true crime story is even more haunting because of the appalling crimes John Sweeney committed against multiple women, making headlines as one of the most terrifying criminals in Britain.
John Sweeney, a former carpenter from Merseyside, is infamous for murdering and dismembering two ex-girlfriends, Melissa Halstead and Paula Fields, before dumping their remains in canals in Rotterdam and London. Delia Balmer, who endured a near-fatal attack by John Sweeney in 1994, is his only known survivor. ITV’s drama captures the torment and trauma she experienced, while a new accompanying documentary, Until I Kill You: The Real Story, features Delia herself recounting her story.
Sweeney’s violent history is documented in Delia’s 2017 memoir, Living with a Serial Killer, which reveals the depths of his cruelty. In Until I Kill You, Anna Maxwell Martin portrays Delia, while Shaun Evans plays Sweeney, bringing the characters' disturbing relationship to life. The drama begins with the pair meeting in a Camden bar, where Sweeney’s charm masked a darker, controlling side that would soon emerge.
The nightmare began with Sweeney’s deceptive charm, as he showered Delia with gifts and affection. However, his facade soon crumbled, revealing a controlling and violent nature. He invaded Delia’s life, criticizing her appearance, questioning her whereabouts, and eventually taking over her home. The emotional abuse quickly escalated to physical violence, culminating in an attack that nearly ended Delia’s life.
In December 1994, Sweeney’s violence erupted in a horrifying assault. He held Delia captive, raped her repeatedly, and subjected her to psychological torture. At one point, he threatened to mutilate her tongue and, in a brutal rage, hacked at her with an axe, leaving her severely injured. Delia’s left little finger was severed in the assault, and she was left with stab wounds. Miraculously, she survived, but Sweeney managed to escape police capture and remained on the run for years, using various aliases to elude justice.
The story took a more sinister turn as authorities linked Sweeney to the murders of two other women. Melissa Halstead, a 33-year-old American model and photographer, was one of his victims. The pair met in 1986, and their relationship was tumultuous from the start. Sweeney was arrested for domestic violence against Melissa multiple times before they moved to Austria. His violence followed her there, culminating in an attack where he tied her up and struck her with a hammer, fracturing her skull. Despite his arrest, Sweeney was released and ordered to leave Austria. The couple moved to Amsterdam, but in May 1990, Melissa’s dismembered body was discovered in a canal in Rotterdam. Her remains were only identified in 2008, thanks to advances in DNA technology.
Another victim, Paula Fields, a 31-year-old mother of three, was found in London’s Regent’s Canal in 2001. Her headless and mutilated body had been cut into six pieces and placed in holdalls weighted down with bricks and tiles. Her head, hands, and feet were never recovered. John Sweeney’s pattern of dismembering his victims and discarding their remains in water was a deliberate attempt to hide their identities, prosecutors argued during his trial in 2011.
John Sweeney’s run from the law finally ended in 2001 when he was arrested for the attempted murder of Delia Balmer. He was sentenced to nine years in prison for that crime and was later interrogated about the murders of Melissa Halstead and Paula Fields. Investigators uncovered a chilling collection of over 300 disturbing sketches and poems in his North London home, depicting violence against women and scenes from his crimes. One of his poems described Melissa’s dismemberment in grotesque detail, while his self-portraits showed him as a devil wielding a bloody axe.
The evidence was overwhelming, and Sweeney was charged with the murders. In 2011, he received a whole life sentence at the Old Bailey, a punishment reserved for the most heinous criminals in Britain. Sweeney refused to attend his sentencing at Belmarsh Prison and received an additional 10-year sentence for perverting the course of justice.
While John Sweeney’s conviction provided some closure, Delia Balmer remains haunted by her ordeal and the systemic failures that nearly cost her life. Despite the severe risk Sweeney posed, he was released on bail after the first attack, leaving Delia vulnerable. The police failed to offer adequate protection, and she was forced to relive the trauma in court. Delia collaborated with ITV on the series to share her story and raise awareness about these failures, expressing that she remains an “angry person” because of the lack of support she received.
The Metropolitan Police continue to investigate potential links between John Sweeney and other missing women across Europe. In 2023, his case was tied to an Interpol appeal seeking to identify 22 women suspected of being victims of violence since 1976. Three of the decapitated women in the appeal were found in Dutch canals, places Sweeney frequented in the 1990s.
Until I Kill You sheds light on Delia Balmer’s unimaginable survival and the horror inflicted by one of Britain’s most dangerous killers. Her courage and determination to tell her story inspire viewers, even as the horror of John Sweeney’s crimes continues to disturb. The series serves as a stark reminder of the importance of justice and support for survivors of violence, as well as the darkness that can lurk behind the most seemingly charming facades.