A teenager found dead near an Oxford city park-and-ride killed himself after fashioning a make-shift 'guillotine' using a drainpipe, rope and a knife.

An inquest into the death of Dmitrij Machankov, 19, of Barns Road, Cowley, Oxford, heard yesterday that he had a history of mental health problems and had been an inpatient at the Warneford mental hospital.

Mr Machankov's body was found near an electricity pylon close to Seacourt park-and-ride, off Botley Road, at about 9am on December 12 by Darren Woods, who was sleeping rough in the area.

He was identified several days later when his father, Valerij Machankov, reported him missing and identified him from a picture prepared by the police.

A report from psychiatrist Dr Rob Chaplin read to the court said that Mr Machankov was feeling suicidal when he was admitted to the hospital. But when he was discharged, he was "mentally well" and had not been suicidal while being treated.

Dr Chapman said Mr Machankov was initially diagnosed with paranoid schizophrenia but was later deemed to have schizo-effective disorder with manic symptoms.

He said: "He had a number of bizarre beliefs, including one that there was a chip inside his head. On no occasion had he given any indication that he would try and remove this chip himself."

The inquest heard that following the identification of Mr Machankov's body, a number of sketches of the make-shift guillotine were found in a cupboard in the room where the teenager, who was working as a builder, was staying.

Det Insp Kevin Elkins said the apparatus with which Mr Machankov had killed himself, which was almost identical to the one in the sketches, was "in the style of a guillotine".

CCTV footage and till receipts were also found showing Mr Machankov bought lengths of black drainpipe and rope from the B&Q store, in Templars Square, Cowley.

Valerij Machankov, speaking through a Lithuanian interpreter, said his son had come to his house to borrow a drill a few days before.

He said: "He seemed very normal. He laughed and came over and we watched a film."

Dr Nicholas Hunt said Mr Machankov had died of sharp and blunt head injuries.

Oxford coroner Nicholas Gardiner said: "In this case, we have evidence that is of course circumstantial but I think very compelling in its direction.

"This satisfies me that he had formed the intention of taking his own life and did so. It is quite clear from what I have heard that your son was a severely ill young man."