Here we take a look at nine for which nobody is yet behind bars.
Anyone with information on any of the murders listed here should contact South Yorkshire Police on 101 or Crimestoppers, anonymously, on 0800 555111.
1. Michaela Hague - 2001
Mum Michaela Hague, who was a sex worker, was stabbed and left for dead on waste ground in Spitalfields on November 5, 2001. Photo: JPI Media
2. Dawn Shields - 1994
The body of 19-year-old Dawn was found in a shallow grave in the Peak District on May 20, 1994. She had been strangled. Photo: JPI Media
3. Nora Tait - 2005
Doncaster grandmother, Nora Tait, 69, was found dead in her home in Stone Close Avenue in Hexthorpe, Doncaster on October 13, 2005 and is believed to have been killed the day before by a blunt force trauma. Photo: JPI Media
4. Vera Cooper - 2002
Vera Cooper, 80, was found strangled in the kitchen of her home in the village of Grimethorpe, near Barnsley, on January 24, 2002. Photo: JPI Media