DETECTIVES investigating one of the region's longest-running murder inquiries are hopeful that DNA advances will help find the killer.

Officers investigating the murder of Ann Heron, who was found lying in a pool of blood at her home near Darlington, 12 years ago today, have been unable to catch the culprit.

Her death is one of only two murder cases on Durham Constabulary's books that remains unsolved, but detectives are hopeful that advances in crime-fighting technology will throw up new leads.

Superintendent John Blake, senior investigating officer, said: " I am in close contact with the forensic science laboratories whose specialists have for the past two years been carrying out an exhaustive re-examination of many of the items received at the time of the murder.

"A lot of the work has been done and there is still more to do.

"The scientists are using techniques, particularly in DNA, which are at the forefront of current technology.

"This has yet to produce the breakthrough I had hoped for but their work is still going on.

"A small team of police officers is continuing to work on the inquiry and both they and I remain convinced there is someone out there with information which could bring this long running inquiry to a speedy conclusion."

Peter Heron found his 44-year-old wife's body at their home, Aeolian House, Morton Palms, between Darlington and Middleton St George, on August 3, 1990.

Her throat had been slashed in what was believed to be a sexually-motivated attack.

The case has become one of the most baffling murders in Britain.

Mrs Heron had spent the afternoon sunbathing in the grounds of the house.

Police still believe a sun-tanned man, aged 35 to 40, who was seen driving a blue car along the drive of the house at about 5pm, when Mrs Heron is thought to have been killed, could hold the key to the mystery.

Anyone with any information about the Heron murder is asked to contact the Holmes Room, at Durham Constabulary headquarters on 0191-386 4929.

* The other unsolved murder case is that of May Rebecca Thompson, 18, of Low Spennymoor, who was found dead in a pool of blood at her home in February 1952.