"I know who killed your son"

When 31-year-old Gary Edwards suddenly collapsed in front of his parents at their home in King Edward Avenue, Broadwater, on December 28, 2002, medical experts said his cause of death was acute asthma and there was never an inquest.

But the woman, who cannot be identified, rocked Roderick and Maureen Edwards' world in November when she told them: "It's been eating away at my conscience for two years. I know how Gary died. One of his friends told me they slipped drugs into his drink without him knowing."

Mr Edwards, 59, said: "You can't imagine our horror. We are devastated '“ worried that our son might have been given a killer drug and the system didn't spot it.Now we are more than two years into this torment and our lives are a living hell. It's like someone has ripped our hearts out and we have lost him all over again." The family say they had concerns about the cause of Gary's death from the very start.

Mr Edwards said: "Gary suffered from asthma but it hadn't affected him for at least a month before he died.So you tell me how can someone in perfect health go to bed, wake up seven hours later and just die? That's been bugging us from day one and no-one has given us an answer."

The couple's suspicions grew when they received a condolence card from one of his closest friends. It read: "...I am so sorry to hear about Gary. He was a good friend ...I am deeply shocked and I hope that you find who is responsible."

Mrs Edwards, 62, who visits his grave at Durrington Cemetery three times a week, said: "What does that tell you?"

Three months later, a mystery man knocked at the door demanding to speak to their son.Mr Edwards explained: "He didn't believe me when I told him Gary was dead. He said: 'I'll have to check this out: people will have to know.' Then he asked where his grave was so he could go and check. I don't know what he wanted but his behaviour was threatening."

For the family, too many questions remain unanswered. Now they are demanding police launch a fresh investigation.

A police spokesperson said: "We are not treating this death as suspicious at this time. But detectives have been approached regarding additional information and this is being looked at."