The parents of a skydiver who plunged 13,000 feet to his death after the cords on his parachute were cut will tonight insist their son did not commit suicide.

Stephen Hilder, aged 20, from Hereford, died while taking part in a parachute jump at Hibaldstow in Lincolnshire on July 4, 2003.

But police ruled out murder after fibres from the sabotaged straps of his parachute were found on scissors in his car, along with his DNA.

An open verdict was recorded at the inquest into his death.

Tonight, in their first-ever interview, his parents Paul and Mary will reveal they believe someone else must have cut the parachute cords, and that their son did not kill himself, although they admit the truth may never be known.

Mr Hilder, aged 54, said: "He did not take his own life."

And his 54-year-old wife said: "It's very difficult to live with not having an answer. We are living through every parent's worst nightmare."

Two skydivers were originally arrested after the tragedy but were later released without charge when the DNA and fibre links were uncovered.

College worker Mrs Hilder said: "Obviously we wanted, and still want, a resolution to this. But one of my biggest fears is that somebody would be wrongly accused.

"Right from the beginning it made no sense that someone would want to do this to Steve."

She went on: "He was funny with a wicked sense of humour, intelligent, bright, energetic.

"He could also be infuriating, like most 20-year-old lads. He could be stubborn, he could be thoughtless - but he could also be very caring."

Mrs Hilder said she last spoke to her son a week before he died, adding: "He was absolutely normal and enthusiastic."

After the tragedy, it emerged Stephen had been worried about failing a college course. He was also £17,000 in debt and had split from a girlfriend.

But his parents dismissed suggestions the problems could have driven him to suicide.

Mrs Hilder said: "Steve was always very conscious of the fact that he was no good with money - it was like water in his hands.

"Although we weren't aware of the level of debt he'd got into, we weren't surprised."

And her husband, who works for the Environment Agency, added: "We saw nothing that would give any hint of any change in his character."

Mr Hilder insisted there was more than one way to interpret the evidence gathered by the police.

He said: "It's quite clear what was done to the parachute - but it hasn't answered the question of when it was done or who did it and for what reason.

"It may well remain a mystery for ever."

* Mr and Mrs Hilder's inter-view is due to be screened at 9pm tonight on Skydiver: Murder Or Suicide in ITV1's Real Crime slot. ..SUPL: