DETECTIVES hunting the killer of North Yorkshire murder victim David Williamson today made a fresh appeal for information exactly six months on from his death.

A team of officers is still searching for the vital breakthrough that will help them track down the killer who struck Mr Williamson, 58, from behind with a blunt object and left him dying on a roadside path just a few hundred yards from his home at Sutton-on-the-Forest, near Easingwold.

Detective Chief Inspector Nigel Boynton, who is leading the investigation, said: "We still believe that someone out there knows something about what happened. I would ask anyone who does to please come forward and tell us. It might just be the breakthrough that we need."

Mr Williamson's sister, Barbara Sherwood, from York, has laid flowers at the scene on the 26th of each month - the day he died.

She has also told how she made a solemn promise to her brother, in a letter which was placed in his coffin, to do all she could to catch his killer.

Mr Williamson's parents, Olive and Isaac, who live in Huntington, are still struggling to cope with their son's death.

DCI Boynton added: "The grieving process for Mr Williamson's family cannot take place properly until the person who has done this is found."

A mass DNA screening programme of about 80 villagers in Sutton-on-the-Forest and nearby Huby, where Mr Williamson had been at the Star Inn the night before he was found, is currently three-quarters of the way through, although no results are yet known.

DCI Boynton said it would take a few weeks before all the samples had been taken and tested against a DNA profile isolated from evidence discovered at the scene.

If no link is found, the screening programme could be extended to others in both villages.

He said detectives were currently sifting through all the information they had collected so far "with a fine-toothed comb" to make sure nothing had been missed.

Anyone with information can contact the incident room on 01904 669489 or call Crimestoppers in confidence on 0800 555111.

Updated: 10:54 Wednesday, September 26, 2001