Janey Godley scatters a dozen family snapshots across the table. Beaming out from each is the face of Sammy Johnstone, the cousin she grew up with, and adored - and whom she, along with a few relatives and friends, will cremate in Glasgow around lunchtime today. "We had a shit life - a Ken Loach movie waiting to be made," she reflects, "But when Sammy came into a room he was always smiling." Judging from the photographs, Janey's observation seems to be true. There's Sammy in his twenties, with all his mates, grinning all over. There's the baby-face that "always pulled the women". There's Sammy with his neighbour, a retired safe-cracker. There's Sammy polishing his shoes - "he was always immaculate" - watched by his adoring niece, then a toddler.

It was Janey who offered to show me the snaps. Perhaps she was trying to restore an identity to Sammy, who was reduced to mere statistic last week when he became the 16th drug addict in Glasgow to die after injecting what health officials believe to be contaminated heroin. His was the 34th in a series of drugs-related deaths over the last two months in Scotland, north-west England and Dublin.

Scientists in Britain and the United States are currently examining tissue from victims and survivors. They are exploring the theory that a batch of heroin, tainted with anaerobic bacteria, proved deadly to the addicts, who all injected into muscle or under skin, after running out of veins. All of the drugs victims suffered total organ failure. Professor Brian Duerden, deputy director of London's Communicable Disease Surveillance Centre, explains that it is impossible to tell whether the epidemic is past its peak, or just getting started.

If the deaths are the result of contaminated heroin, no one knows how big the offending batch was, how widely distributed it was, or how quickly it will be used. A worldwide search is currently underway for similar cases, and the scientists will reveal their latest findings tomorrow.

Looking through the press clippings, you can't help feeling that had 34 people died after eating contaminated meat, or even tainted tobacco or alcohol, there would have been a huge interest in the victims. Instead the coverage has concentrated more on the "mystery bug" than those it has killed. The thought occurs that Britain is losing little sleep over the 34 dead addicts.

Janey, who is also a successful stand-up comedian, isn't surprised at the general indifference. In her stage routine, she takes a swipe at the hysterical public reaction to the death of Diana, Princess of Wales, and contrasts it with the situation in Glasgow, which is now the heroin-injecting capital of Europe.

Here, she says, women addicts are dying every day, leaving children behind, and no one gives a damn. Heroin addicts, she argues, have become Britain's untouchables.

When Sammy died last Monday, aged 34, he was living in a hostel, selling the Big Issue and "shooting" heroin most days. But just a few years earlier, he had had a job, a car, a girlfriend, relations who loved him, and a life. This week the Big Issue, which says that another three of its vendors are among the 16 victims, is calling for an inquiry into Sammy's death.

Jim Brown, the outreach worker who took Sammy to hospital three days before he died from organ failure, says that despite the current scare and the fact that Sammy "looked like a man who was dying", his examination lasted less than 15 minutes. He was then sent home. "I just could not believe it when they did not admit him," he says. For its part, the Big Issue points out that it has complained about the standard of health care for addicts for years.

Janey Godley says she is reluctant to blame anyone for Sammy's death - "except Sammy for taking heroin in the first place". It is now seven years since she was told that her cousin Sammy "was chasing the dragon". She confronted him; Sammy denied it; and a gulf opened up between them. Even after his death, it is clear she is still angry at him. But why did Sammy start? "If I knew that I would have a Nobel prize," she says.

Surprisingly, Janey does not blame a chaotic childhood. She points out that she suffered abuse as a child and that she didn't turn to heroin. Still Sammy's childhood was undeniably grim. Janey and Sammy were raised on council estates in Glasgow's East End, in troubled families. Even as a child Janey remembers widespread alcoholism and drugs abuse. Women on her estate drank too much and popped Valium - prescribed by doctors and borrowed from friends - like Smarties. Drugs were always around, it was the type that kept changing.

"Sammy's dad, Jim, was a wee, hard-working, long-distance lorry driver," Janey recalls. "But my Aunty Cathy had a lot of problems." Sammy's parents were always splitting up, and he and his younger sister, Jacqueline, often came to stay with Janey's parents. In 1980, when Sammy was 15, his father committed suicide. His mother killed herself three years later.

Jacqueline went into care. And shortly before his mother died, Sammy came to live with Janey, who despite her own difficult childhood, had married and now ran a pub in the Calton, on Glasgow's east side. "We cut Sammy's hair, washed him up and put him behind the bar," she remembers. "He had never had stability or responsibility but he got right into it."

Janey says that the irony is that Sammy spent his early and mid-twenties surrounded by heroin but never touched it. He did smoke dope, but then "so did everyone".

Heroin had arrived in the Calton in the late Seventies, long before it reached surrounding neighbourhoods. Janey made its acquaintance within days of taking over the Weavers pub in 1979. "I remember sitting in a flat and six people taking the needle but I didn't," she says. "Those six are all dead."

In the Eighties, Godley says there was hardly a tenement in the Calton which could not boast a heroin death. The pub was virtually next door to Calton Athletic, the respected drugs project, which provided technical advice to the makers of Trainspotting. "It was not as if Sammy did not know what drugs do," Janey says. "We went to funerals where the brothers and sisters of the dead would turn up full of heroin."

Throughout the Eighties and early 1990s, Sammy worked hard in the pub and lived in a flat above. Janey remembers Sammy's delight when she bought him a gold sovereign ring he coveted and how she helped him buy "the motor" he had always wanted. "He had a wicked sense of humour and was never a depressive," she says. "He was a skinny thing but always so confident. He was no Richard Gere but women loved him. I would have known if he was a junkie."

But Sammy's death has raised doubts. And finding out when he first started taking heroin has become Janey's obsession. She gave up the Weavers in 1994, but on a walk on Sunday through the old neighbourhood she sought out Sammy's old friends to ask if they knew when he started.

The information is conflicting. Some old friends reassure her that Sammy never touched the stuff in the Eighties. But she wonders now about the months in 1984 when he "drifted away" for a while. And although he was affectionate, she remembers now that he didn't share everything, that he always kept something in reserve. Was he experimenting then? The mother of a child she never knew Sammy had fathered - Sammy, it transpires, had five children by three different women - has told her that he was, indeed, shooting up in the Eighties. But she remains convinced that if this was any more than flirting she would have noticed.

What makes Janey so angry with Sammy is that they came through so much "shit" together, and then, just when life was getting better, he seemed to throw it all away. She is angry, she now realises, partly because his addiction makes her feel she failed him.

Janey only saw Sammy a few times in the past seven years. One occasion, soon after he left, is still vivid. Sammy had returned to repay some money that he owed; it was clear that he had already changed. "He was very agitated and frantic," Janey remembers. "He said he had not eaten for a week because he had no money. I asked why he had no money and he shouted that he was not taking drugs." After that Janey's husband, Ian, kept in contact with Sammy. "He said Sammy looked like any addict on the street."

The five Big Issue vendors who knew Sammy best only ever knew him as an addict. All addicts themselves, they seem to mourn him with the same morbid resignation as they mourn Morag Conlon, Paul McMahon and Norrie McLeod, the three other vendors (all in their twenties) that the Big Issue claims have been identified as victims of the mystery bug.

"God rest him but he's in a better place, just like Norrie," says Joseph Collins, who once shared a flat with Sammy on Glasgow's tough Castlemilk estate. Before that, the vendors say, Sammy had lived on the streets. In Castlemilk Sammy already had a £30-a-day habit.

Collins remembers Sammy as a generous man, willing to share what smack he had. That was rare. "Most addicts," laughs Paul Hughes, who lived in the same Salvation Army hostel as Sammy, "only want to save what they have for their next charge." It was Hughes, who first alerted Big Issue staff to how ill Sammy was. He says that in the months before he died, Sammy's body was "fucked because he had run out of veins and he had holes in his legs and he was skin popping." Then Hughes pauses. "You would think Sammy's death would put us off but it doesn't."

There's also a morbid pride in injuries. A 12-inch abscess at the needle's point of entry is apparently one of the symptoms of the heroin contamination. But all the vendors have had abscesses. The legs of William Allan are weeping so much that the poison is seeping through his jeans and his legs are so painful he walks on his tip toes. The general consensus seems to be that Allan is getting as bad as Sammy was before he died. The trouble is, they all agree, that compared to heroin, health, families, "the ladies" and life itself all mean nothing.

Did Sammy ever speak about the life he had? Big Issue staff say that while the Sammy they knew could still be humorous one-to-one, he had lost his outgoing nature, and became a man who kept himself to himself. "He used to complain he never got to see his kids," says Hughes. "And he spoke about his motor. He had to sell the motor but he was always saying he would save up and get a new one. Of course he never did." And did he ever speak of coming off the drugs? Only latterly it seems, as his body was failing.

Much has been made of the addicts' disregard of health board advice to smoke rather than inject heroin, at least until the current crisis is over. But many addicts appear to doubt the existence of the "mystery bug". With an estimated 12,000 injectors in Glasgow, the vendors point out, addicts are always dying. As they see it, nothing has changed. Norrie, they concede, might have died from the bug because his demise was so sudden. "One minute he was fine, the next he was a skeleton in a jacket." But Sammy was so ill already, and Morag "had veins left so she didn't inject into muscle."

Of course it is convenient for addicts who continue to inject to believe the crisis is a red herring. But even a few drugs-programme workers seem to share their suspicion that it's all a smoke screen to hide rising numbers of deaths and the inadequacy of the health board's anti-heroin strategy.

All Sammy's old flatmate Joseph Collins wants to know is if the vendors will be welcome at his funeral. "You know most people just think we're the scum of the earth," he says.