THE girlfriend of a York man who drowned in a river in the city has warned people to be on their guard against the drink-spiking she fears may have cost her boyfriend his life.

Scientists found drug traces in Peter Critchlow's body after he was found dead in the River Foss, but Dawn Harrison says Peter was "totally against drugs". She believes his drink may have been spiked with speed on the night he vanished.

With the first anniversary of Peter's disappearance this weekend, Dawn told how family and friends were stunned at the post-mortem findings.

If Peter's drink had been spiked, Dawn believes this may have disorientated him. That could explain why, after a night out in York, he took an unexplained diversion away from his house in The Groves towards the River Foss.

Speaking in detail for the first time about her "nightmare", Dawn told how she was struggling to come to terms with the loss of a "caring" boyfriend who she misses terribly and "wanted to spend the rest of her life with".

An inquest heard how Peter had large quantities of alcohol, and amphetamine in his system when his body was recovered last December. The coroner recorded a verdict of accidental death and said Peter must have accidentally tripped and fallen in the river.

The 25-year-old civil servant vanished a month earlier and an extensive police search was launched.

Dawn accepts Peter, originally from Northampton, was drunk on the night he vanished but maintains he never knowingly took drugs.

"There was never anything to say he took the drugs himself," said Dawn, 25, who works for Norwich Union in York.

Urging people to be cautious about drink-spiking, she added: "I'm sure that he would never have taken them himself and everyone that knows him thought the same.

"I was his girlfriend for two years and he was totally against drugs. I never heard him talk about them. I don't think for a minute he would have taken them himself.

"I don't know how they got in his system. Maybe someone did put them in his drink."

York St John College recently ran an awareness campaign in which straws were placed in the drinks of unwary students to show how easily their drinks could have been spiked.

Meanwhile, police say there are no suspicious circumstances about Peter's death, and Dawn says she "doesn't have a clue" why he ended up in the river at Foss Bank.

His last sighting was at a Heworth Green phone box. From there he should have made his way to The Groves.

"There are still a lot of unanswered questions," said Dawn.

Updated: 10:09 Thursday, November 11, 2004