A MAN is helping detectives with their investigation into the mysterious death of 34-year-old family man Paul Simpson.

The local man, in his 20s, was being held at Darlington police station last night.

Officers involved in the case have also revealed details of a vehicle they believe could hold vital clues.

The details of how Mr Simpson, a mature student from Darlington, suffered a fractured skull are still unknown.

The father-of-two was found in Askrigg Street, Darlington, at 2.20am on Sunday, March 11, by a patrolling police officer, ten minutes after he left a friend's house in Leyburn Road for the 400-yard walk home. He died the next day.

A post-mortem examination showed that Mr Simpson had died from head injuries, believed to be sustained in a heavy fall. Marks on his face suggested that he had been punched.

A dark green Isuzu pick-up at the centre of the investigation is thought to have pulled into Askrigg Street and stopped near a telephone box at about the time when Mr Simpson was injured.

Detective Superintendent Harry Stephenson, who is leading the investigation, confirmed that sightings of the vehicle had become a vital element of the inquiry.

He said all the indications pointed to Mr Simpson having been punched in the face immediately before falling.

Anyone with information is urged to contact the incident room at Darlington police station on (01325) 467681.