POLICE plan to reconstruct the last moments of a dog walker fatally injured in a mystery incident.

George Button, 53, of West Rainton, near Durham City, died on Wednesday without regaining consciousness from a head injury he suffered on Monday night.

He received a single blow, delivered with tremendous force, to the back of his head while walking his black and white border collie, Laddie, in Mark's Lane, a country road on the outskirts of West Rainton.

Police still do not know if Mr Button, a council electrician, was the victim of an assault or was hit by part of a passing vehicle.

On Monday night, a detective will follow the same route with Laddie.

Police are disappointed that a tall man with a dog seen talking to Mr Button still has not come forward.

"We believe we have largely pieced together Mr Button's movements between the time he left home and the time he was found," said Detective Superintendent Dave Jones.

"The only gap in the jigsaw is the failure of that man he was talking to in the lane to come forward. He could obviously provide us with important information."

Police are to put up posters up in the village echoing their calls for help.

Experts from the National Crime Faculty and the Transport Research Laboratories are being consulted in the hope they can identify how Mr Button's injuries were caused.

Police are keeping an open mind but believe he may have been hit by a passing vehicle.

Mr Button left the home he shared with wife, Christina, and daughter, Laura Jane, seven, at 7pm, and was found unconscious on a verge half an hour later.

Anyone with information is asked to call police 0191-386 4929 or Crimestoppers on (0800) 555 111.