FORENSIC experts spent last night carrying out the rare and painstaking process of exhuming the remains of a woman whose death has baffled police for more than 30 years.

The unidentified woman was found in undergrowth close to Sutton Bank, near Thirsk, North Yorkshire, in August 1981.

Despite an extensive investigation at the time, her identity and the cause of death were never established.

As part of a cold-case review of her death, coroner Michael Oakley sanctioned the exhumation of the woman’s remains, from an unmarked grave in Malton cemetery.

The graveyard, where the exhumation began at midnight, has been closed to the public, with uniformed officers standing guard at each entrance. A 7ft fence provided privacy, while the grave was shrouded in a white tent.

Extra care had been taken to protect the memorials near the woman’s grave, with protective wrapping placed around headstones in the immediate vicinity.

About 20 people were involved in the overnight operation, including police officers, led by Detective Superintendent Lewis Raw.

Also present was a pathologist, a forensic archaeologist and crime scene investigators.

The Reverend Simon Rudkin, force chaplain, conducted a blessing shortly before the start of excavation work.

Det Supt Raw said it was hoped DNA analysis of the remains – in particular the teeth and thigh bone – would shed light on the woman’s identity and cause of her death.

He said: “The identity of this woman is key to this investigation.

When we establish who she was, and the circumstances in which she came to harm, that could result in another criminal investigation.

The advancement of forensic technologies in the past 30 years is something that we hope will help us make progress.”

Asked why the operation was carried out late at night – the remains of the unidentified woman left the cemetery at 7.45am this morning – Det Supt Raw cited dignity and privacy.

Officers in the initial investigation were unable to even pinpoint the identity of the man who reported finding the woman’s body.

Det Supt Raw said: “An unknown man rang Ripon police station, but said they could not say who they were on national security grounds. I urge that person – if they are still alive – to come forward.”

It is hoped that forensic results will be known within four weeks, said Det Supt Raw.

The remains will be returned to the cemetery tomorrow morning for a re-interment service at 11am.