DETECTIVES investigating an unsolved murder 14 years ago have appointed a "cold case" expert to help track down the killer.

The year-long review into the murder of Darlington woman Ann Heron is the first of its type to be undertaken in Durham Constabulary's history.

Ian Phillips, a former detective inspector with Darlington police, will handle the task of sifting through masses of evidence to try to uncover the murderer.

Mrs Heron was found in a pool of blood by her husband at her home in Middleton St George on August 3, 1990.

The 44-year-old mother, who had been sunbathing on what was the hottest day of the year, had had her throat slashed.

The officer heading the investigation, Detective Superintendent Dave Jones, worked with Mr Phillips before his retirement and asked him to look back over the case.

As well as sifting through the evidence, he will use modern methods and new technology - similar to the cold case team in the hit BBC show Waking the Dead - in a bid to make a breakthrough.

Det Supt Jones said: "Normally, when you do a case you get information coming in a piece at a time.

"When you come to something fresh like this, you are confronted with information that has been collected over 14 years.

"It's a full-time task, and police officers have to deal with other cases as they arrive. Ian will be able to dedicate himself specifically to this."

Throughout the investigation, more than 1,500 forensic samples were submitted for analysis, 7,000 people were questioned and more than 4,400 statements taken.

The documents associated with the case have been estimated to weigh approximately a quarter of a tonne.

Mr Phillips said advances in forensic and DNA technology would play a very large part in his review.

He said: "There's quite a number of additional exhibits that can be reprocessed, which may give us that other little piece of information."

It is anticipated the review will take a year. The report will then be passed on to the chief constable and the Crime Prosecution Service.

Det Supt Jones said: "They will have responsibility for deciding, on the basis of any new evidence we are looking to uncover, whether there is a reasonable chance of securing a conviction should anyone be arrested after this length of time."

He said that although the time difference would inevitably make it more difficult for a conviction to be established, he was still hopeful the investigation could be successful.

"There's still a distinct possibility there are people out there who know exactly what happened, and we obviously still want to hear from them.

"Also, the person who did this has had to wake up every morning for the past 14 years knowing what he has done."

The Heron case is one of only two unsolved murders in County Durham. The other is that of May Rebecca Thompson, who was killed in Spennymoor in 1952, which is also still undergoing investigation.

Det Supt Jones said: "As far as we're concerned, this case has never gone cold."