The South Yorkshire cold case team investigating crimes from the 1960s

In 2019, the unit re-examined the victim’s jacket sleeve and a DNA swab was a match for Ellis, who was by then in his 60s and living in Bristol. He was later jailed.

There are 35 unsolved murders in the force area, including that of 13-year-old Anne Dunwell, who was strangled with her own stockings and sexually assaulted in the mining town of Maltby.

She had been returning home after visiting her aunt when she was attacked. Although new lines of inquiry were explored in subsequent years, her killer was never identified and Anne’s father died without seeing anyone held responsible.

A more recent homicide was in 2001, when Wath-upon-Dearne resident Brian Metcalfe was found murdered after a night out in local pubs. Mr Stopford led a fresh appeal on the 20th anniversary of the 43-year-old’s death and told the public that officers thought the answer to the mystery lay “in the local community”.

Mr Stopford said there were challenges around old evidence from the 1960s and 70s, as some items had been contaminated before DNA testing methods came into use.

“Exhibits weren’t handled as carefully before DNA was utilised in investigations, so we get more cross-contamination from the detective, scenes of crime officers and even scientists”, he explained.