Dawn Shields: Police reopen 1994 strangle murder probe
Police have reopened an investigation into the murder of a teenager who was strangled and dumped in a shallow grave 25 years ago.
The body of 19-year-old Dawn Shields was discovered buried under rocks in the Peak District on 20 May 1994.
South Yorkshire Police said she led a "troubled life" and was pressurised into prostitution from the age of 14.
The force said advancements in DNA techniques may now help find her killer.
Ms Shields, from Pitsmoor in Sheffield, was last seen getting into a car in Broomhall on 14 May 1994.
At the time of her death, she was working as a prostitute to support herself and her 11-month-old son.
Police said Ms Shields' body was found "by chance" concealed by rocks when a National Park warden took a different path to his usual route up Mam Tor near Castleton.
She was discovered naked and her clothes have never been found.
The force's major incident review team said it was re-examining evidence for previously undetected traces of DNA.
Former detective Dave Stopford, who leads the team, said: "Advancements in DNA techniques are being made all the time and less and less DNA is now needed to identify someone."
He said the investigation was "far from straightforward" and cross-contamination was a major issue as investigators handling evidence did not always wear masks and gloves in the 1990s.
Ms Shields' death has been re-examined several times in connection with the deaths of other sex workers, including 25-year-old Michaela Hague from Sheffield who was killed seven years later.
But Mr Stopford said no links had been found between her death and the murder of other prostitutes.
A change in allegiances or loyalties over the past 25 years could mean someone now feels more able to come forward, he added.