Two days before Christmas 1994, mother-of-two Tracey Mertens was doused in petrol and set alight in a churchyard, suffering horrific burns and dying 12 hours later.
This week marks 21 years since her death, but no one has ever been convicted in connection with the 31-year-old's murder.
Police have renewed their appeal for information about the crime, with a £30,000 reward offered for details leading to the arrest and conviction of those responsible.
"Tracey met a violent and horrific death at the hands of her killers," said Detective Inspector Gary McIntyre, from Cheshire Police.
Ms Mertens, who lived in Rochdale, travelled to Birmingham on December 22, 1994, to collect a benefits book from her former home in Cattells Grove, Nechells.
She stayed overnight at her sister-in-law′s and visited her former home the next morning.
Shortly before midday on December 23, she answered a knock at the door of the Cattells Grove home and was confronted by two black men.
Police believe she was abducted and bundled into the back of a yellow Ford Escort, before being driven to Christ Church in Eaton, Cheshire, where she was set on fire and left to die.
A passer-by came to her aid and she was rushed to hospital with 95% burns to her body, telling detectives what happened before dying 12 hours later, early on Christmas Eve.
DI McIntyre added: “She was so brave and told detectives as much as she could before she died. That information was vital for the investigation team at the time and numerous lines of enquiry were pursued."
The subsequent investigation never led to any convictions and, despite numerous appeals over the years, including two on BBC Crimewatch, police are still hunting her killer.
DI McIntyre said: "Someone out there must know who is responsible for Tracey′s murder and I would personally appeal to them to come forward and speak to us.
"Tracey’s family are preparing to spend another Christmas without her – an experience that remains a difficult one for them all.
"Although a lot of time has passed since that day, I do firmly believe that there are still other people out there who may have witnessed what happened and would appeal to them to come forward."