Detectives probing the death of a North Yorkshire man today confirmed he was murdered.

Further examinations by pathologists and expert advice from neurosurgeons revealed David Williamson died as a result of a blow to the back of the head which was probably caused by a blunt instrument.

Mr Williamson was found on a roadside path at 5.30am last Monday, a few hundred yards from his home at Sutton-on-the-Forest, near Easingwold.

The 57-year-old had suffered a fractured skull. He died later in hospital.

More police have been called in to the investigation, making a 25-strong team of detectives.

Officers were trying to establish a motive for Mr Williamson's killing.

Acting Detective Inspector Kevin Ross, leading the inquiry, revealed that on Sunday more than 50 vehicles were stopped in the area that Mr Williamson was found and many had been able to offer information to the inquiry.

Police were now following up new leads and officers were particularly keen to trace the occupants of a dark coloured vehicle which was parked near the scene at a building known as Bentley's or Hardy's barn.

DI Ross said that if the occupants had been a courting couple or someone reluctant to come forward for other reasons, he was happy to speak to them personally.

Police search teams have been scouring the roadside and fields between the spot where he was found and the Star Inn, Huby, which Mr Williamson had visited on Sunday.

There had been a party at the pub and police were looking for anyone who might have taken photographs at the party.

DI Ross said detectives had now contacted nearly all the people who had been in the Star Inn.

Officers also appealed to anyone who had been at the pub but who had not yet come forward to do so.

Police were keeping an open mind about Mr Williamson's movements having had contradictory reports.

Some witnesses reported him leaving the pub at 4pm while others said he did not leave until 11pm.

DI Ross said there had been nothing to suggest anything which happened in the pub could have led to Mr Williamson's death.

"There was a party and the normal raucous behaviour but there were no violent arguments or fights."

DI Ross said the appeal was particularly targeted at people in Huby and Sutton-on-the-Forest.

"It's the people of those villages that we want to appeal to come forward and give us evidence that will help us get to the bottom of how David died.

"There's a lot more they can tell us if they just search their minds and search their consciences."

A 27-year-old local man who was arrested and interviewed by police on Saturday and later released on bail is due to report back to York police station on May 3.

Updated: 12:13 Thursday, April 05, 2001