The murder of Julia Martha Thomas, dubbed the "Barnes Mystery" or the "Richmond Murder" by the press, was one of the most notorious crimes in the Victorian period of the United Kingdom. Thomas, a widow in her 50s who lived in Richmond, London, was murdered on 2 March 1879 by her maid Kate Webster, a 30-year-old Irishwoman with a history of theft. Webster disposed of the body by dismembering it, boiling the flesh off the bones, and throwing most of the remains into the River Thames.
It was alleged, although never proven, that Webster had offered the fat to a publican, neighbours and street children as dripping and lard. Part of Thomas's remains were subsequently recovered from the river. Her severed head remained missing until October 2010, when the skull was found during building works being carried out for Sir David Attenborough.
After the murder, Webster posed as Thomas for two weeks but was exposed and fled back to Ireland at her uncle's home at Killanne near Enniscorthy, County Wexford. She was arrested there on 29 March and was returned to London, where she stood trial at the Old Bailey in July 1879. At the end of a six-day trial, Webster was convicted and sentenced to death after a jury of matrons rejected her last-minute attempt to avoid the death penalty by pleading pregnancy. She finally confessed to the murder the night before she was hanged, on 29 July at Wandsworth Prison. The case attracted huge public interest and was widely covered by the press in both Britain and Ireland. Webster's behaviour after the crime and during the trial further increased the notoriety of the murder.