Serial Killer Known as 'Scalp Hunter' Died in Prison Without Revealing Full Extent of Crimes

Serial killer John Sweeney, who went by the moniker "Scalp Hunter," died in prison last week at age 69 from cancer, taking with him the potential secrets of other murders he may have committed. Sweeney was serving a life sentence for the brutal killings of his former girlfriends Melissa Halstead and Paula Fields, whose dismembered bodies were found in canals in London and the Netherlands.

Retired Detective Chief Inspector Howard Groves, who was instrumental in Sweeney's capture, expressed a lingering disappointment that the killer never provided closure for the victims' families by revealing the locations of any other remains or admitting to further crimes. "I feel for the families who will never have closure – that would always be something that they can't change," Groves told The Crime Desk. "I suppose he's somebody who feels that they have the upper hand, 'I will always take this secret with me to my grave'. There are people who are like that. There's no humanity in them."

Sweeney, a carpenter by trade, was convicted in 2011 of murdering Halstead and Fields. Halstead, an American model from Ohio, was found in a Rotterdam canal in May 1990, but her remains were not identified for 18 years. Fields, a 31-year-old mother, was discovered in February 2001 in six holdalls floating in Regent's Canal in London. Her body had been cut into ten pieces. The mutilation of the bodies was noted by the sentencing judge as a serious aggravating feature of the murders.

During his trial, Sweeney exhibited extreme arrogance, reportedly inserting earplugs to block out the evidence presented against him and refusing to leave his cell for sentencing. "He sat there with earplugs in his ears for the majority of the trial. I think that was just the contempt that he had for the officers, family members and jury," Groves recalled. "My view is, if you're not guilty, ... you stick plugs in your ears, you're basically saying, I don't want to hear any of this."

Investigators linked Sweeney to the crimes partly through advances in DNA technology, which connected him to an earlier axe attack on an ex-girlfriend, Delia Balmer. Balmer survived the assault after a neighbor intervened.

Hundreds of Sweeney's disturbing paintings and poems were discovered at his residence, depicting violent acts against women, including references to "666" and himself as Satan. One poem chillingly referred to Melissa Halstead: "Poor old Melissa. Chopped her up in bits. Food to feed the fish. Am*dam was the pits."

While police questioned Sweeney about the disappearances of three other former girlfriends, he was never charged in connection with those cases. Dutch authorities also investigated claims that Sweeney was responsible for the deaths of two German men. Police suspect he may have committed additional murders in the UK, the Netherlands, and other parts of Europe, where he claimed to have had between 30 and 40 relationships.

Groves noted that the investigation into Sweeney's crimes was a significant challenge, involving meticulous work and reliance on forensic evidence, Sweeney's artwork, and testimony from associates. He also highlighted that Sweeney's case was among the first instances of British and Dutch police forces collaborating on a murder investigation.

Sweeney's conviction and the subsequent investigation were the subject of a 2024 four-part ITV drama, "Until I Kill You," based on a book by survivor Delia Balmer.

A prison service spokesperson confirmed Sweeney's death and stated that the Prisons and Probation Ombudsman is conducting an investigation, as is standard procedure for all deaths in custody.