The Oxford family of a computer expert who is feared dead after mysteriously disappearing from his home have appealed for help in finding him.

Jonathan Dolton disappeared almost two months ago after visiting a friend. Detectives at first believed he may have been abducted, but now believe he could have been killed.

Mr Dolton, who attended Botley County Primary and the Matthew Arnold schools, has failed to contact his family since his disappearance.

Detectives said their inquires had failed to reveal any new clues.

Alan and Sheila Dolton, of Stanley Close, Botley, said their son had failed to acknowledge either of their birthdays since his disappearance. He has also missed his sister Nina's 18th birthday, despite being devoted to her. Mrs Dolton said: "Obviously we are very worried for him. We don't know if he's alive or dead. The police have been searching the area and making inquiries but we are no nearer to finding out what has happened to him. We can't believe that anyone would have wanted to harm him.

"He was a bright, keen young man of 20 with everything to live for. He wouldn't just disappear.

"Jonathan was very talented with computers and this last year had been helping to establish a new computer business in Stony Stratford.

"Computers have been a big part of Jonathan's life since he was a boy and he had the chance of a rewarding career ahead of him." Mr Dolton, who moved to Milton Keynes a year ago, left a friend's house in nearby Wolverton shortly before midnight on February 24.

He is thought to have returned home to Stony Stratford, but disappeared early on February 25.

Detectives believe he could have been disturbed at his home.

His passport and clothing were found at his home and no withdrawals have been made from his bank account since his disappearance.

His four-wheel-drive Diahatsu was found abandoned behind some shops elsewhere in Milton Keynes on the day he vanished. Thames Valley Police, who have set up an incident room, said they have no reason to believe Mr Dolton would have taken his own life.

Det Supt Steve Morrison, leading the investigation, said: "We do feel now that something really bad has happened to him.

"We still hope for some clues as to his whereabouts, but I fear the worst has happened to Jonathan."

He said the setting up of an incident room -- standard practice in a murder investigation, but not usual in the case of missing people -- gave some indication of their fears. Mr Dolton is white, 5ft 10in, of thin build, with mousy short hair. He has a barbed wire tattoo on his left arm.

Anyone with any information is asked to call the incident room on 01908 686000, quoting reference number 602 of 17/4/2, or Crimestoppers on 0800 555 111.