Police are to reinvestigate the "appalling murder" of a teenage drama student 20 years ago.

The body of Amanda Duffy was found in wasteground in Miller Street, Hamilton, South Lanarkshire, in the early hours of Saturday, May 30, 1992. The 19-year-old had been battered to death, with her nose and jaw smashed and twigs and branches forced into her mouth.

A man, Francis Auld, later stood trial for her murder but the jury in the case returned a not proven verdict.

The re-investigation comes after the controversial double jeopardy rule, which prevented an accused from being prosecuted for a crime of which he or she was earlier acquitted, was scrapped last year by the Scottish Parliament. Prosecutors are currently reviewing cases which could be prosecuted under the Double Jeopardy Act.

The Crown Office also set up a new unit last year to tackle unsolved murders and serious crimes. The unresolved homicide database contained 93 unsolved cases dating back to 1942, including the murder of teenager Elaine Doyle in 1986.

Strathclyde Police said yesterday they had set up an incident room at Larkhall police office and urged anyone with information to contact them.

Detective Superintendent Alan Buchanan said: “It is now 20 years since the appalling murder of Amanda and every day her family have to live with the knowledge that the person responsible for the murder of their daughter has never been brought to justice.

“I believe that certain people have information in relation to Amanda’s murder that they are withholding, perhaps from a sense of misguided loyalty, and may be reluctant to come forward with that information.

“I now need those people to look at their consciences and think of Amanda’s family and friends who have been through the worst experience imaginable in losing a loved one in the most horrific way.”

Ms Duffy was an aspiring actress who was a student at Motherwell College. She had been called to audition at the Royal Scottish Academy of Music and Drama (now the Royal Conservatoire of Scotland) and was on her way home from a night out celebrating with friends when she was attacked in 1992.

Mr Auld stood trial for her murder later that year, with the court hearing that a bite mark found on her breast was a perfect match for his teeth. He claimed it was a love bite and said the teenager had later walked off with a stranger.

The decision by the jury to reach a not proven verdict sparked calls for the controversial option in Scots law to be scrapped.

In 1995 Miss Duffy’s parents, Joe and Kate, won a civil action against Mr Auld and were awarded £50,000. They also set up Petal, a support group for the families of murder victims, and helped lead calls to scrap the double jeopardy rule.

Police have now set up a dedicated email address for the investigation: AmandaDuffyInquiry@strathclyde.pnn.police.uk