A caller who left a garbled message with police about the murder of a defenceless teenager could hold the key to solving the crime, detectives said yesterday.

Twelve months since Scott Pritchard was bludgeoned to death on his doorstep in Sunderland detectives renewed their appeals for help.

The 19-year-old unemployed man from Hendon was found with severe head injuries outside the Lindsay Close home he shared with his mother at 7pm on January 7 last year.

At the time of the attack he was on crutches with his foot in plaster.

Police have not given up hope of catching his killer and want to hear from a man who left a message the day after the brutal attack.

Detective Chief Inspector Andy Potts said: "He gave us some information about who he thought the person responsible for Scott's death was.

"It was very useful but it is only half of the information that we need."

Det Ch Insp Potts said the Hendon community had responded extremely well to police inquiries made after Scotts's death.

Officers have collected 1,394 statements, 2,141 exhibits and carried out 115 interviews.

A man was arrested last January on suspicion of murder while a 34-year-old and 16-year-old were arrested on suspicion of assisting an offender and bailed.

They were re-arrested in September on suspicion of murder and conspiracy to murder but later released without charge.

Det Ch Insp Potts said: "We have since proved that the those people were not linked with Scott's death.

"Somebody somewhere has a vital piece of information which will piece together the jigsaw puzzle.

"I still believe that in such a small close-knit community someone must know something about this incident, whether they heard or saw it at the time or heard something afterwards.

Det Ch Insp Potts said people should come forward to help the popular young man's grieving family.

He added: "Scott's mother, brother and sister have a daily reminder of the incident because they travel back and forth to their house everyday.

"It has been a traumatic year for them and it has been their first Christmas without Scott.

"They need some closure on this, some solutions, and is why we are appealing for help."

Anyone with information call the incident room on 0191 563 6946 or Crimestoppers on 0800 555 111.