THE sister of North Yorkshire murder victim David Williamson has revealed her final promise to her brother: she will not rest until his killer is caught.

Barbara Sherwood, from York, told of her solemn vow as she laid flowers at the spot where her brother was found dying exactly four months before.

She said: "I personally promised David in a letter, which was placed with him in his coffin, that I will do everything that is possible to ensure his murderer is caught."

The bouquet, which she laid by the roadside path just a few hundred yard's from her brother's home in Sutton-on-the-Forest, near Easingwold, carried a heartfelt message asking "Why?" and urged people to call the police with information.

She said: "We need to know why. Only when the person responsible is brought to justice will our family feel that David is truly at rest."

The 58-year-old bachelor was found unconscious with a fractured skull on Monday, March 26, and died later the same day.

Examinations showed he had been struck from behind with a blunt object.

Mrs Sherwood said: "One never imagines the word 'murder' would ever enter your family circle. I cannot describe how this has emotionally affected the whole family.

"Some days we seem okay, then the next day we are in turmoil."

Mrs Sherwood, 55, who was with her husband, Mike, has laid flowers at the scene each month on the 26th.

Her parents, Olive and Isaac, who live in Huntington, have also visited the spot.

She said: "My parents, who are both in their eighties, are completely shattered and broken - still believing that it is a dream.

"My mother keeps breaking down and my father, who only recently underwent a serious operation, is still very weak and is trying his hardest to support my mother even though he himself is heartbroken."

She pleaded for people to come forward with information.

"Please help us to find my brother's murderer," she said.

"The frightening element of my brother's murder is that the person responsible for his death is capable of doing it again and then some other family could go through the horror and devastation we are experiencing."

Detective Constable Simon Dixon, one of the inquiry team, said: "I would like to reassure David Williamson's family and the public that we remain as determined as ever to catch the person responsible for his murder."

Despite extensive inquiries, appeals on BBC's Crimewatch and the offer of a £5,000 reward from Crimestoppers, detectives are still being hampered by lack of information.

They are particularly keen to hear from anyone who saw Mr Williamson after he left the Star Inn at nearby Huby the night before he was found or who saw a dark-coloured vehicle parked at Bentley's Barn, next to the scene, on the night.

Anyone who can help should call the incident room on 01904 669448 or call Crimestoppers on 0800 555111.

Updated: 11:20 Friday, July 27, 2001