For many weeks afterwards, the school with no name remained just as it was when the siege ended: frozen in time, a memorial to those who had died and to the suffering of those who had survived. Many people in the town could not bear to visit the school; others could not keep away, and went there to stand in silence or weep or leave tributes, or simply wander among the ruins. Some left wreaths, others left bottles of water, cans of fizzy drinks or cartons of juice - for all those who had died thirsty, denied water by the terrorists. As time went on, the school became a stopoff for sightseers too: a party of footballers from the Russian city of Perm, some American Scientologists from Moscow, an endless trickle of film crews and reporters.

There were no fences, no gates to keep visitors away, despite the precarious state of the buildings after the explosions, the fire, the prolonged gunfight and the final shelling on the evening of the third day from Russian army tanks.

On the floor in the kitchen were lace curtains stained with blood. In a nearby hallway a female suicide bomber, a shahidka, had burst like a balloon when she exploded, the spray of her remains, including a clump of hair, visible in an arc across the walls and ceiling. There were traces of the other shahidka in an adjacent classroom.

I was told how a Russian soldier on cleaning duty had collected her head from a corner of the room, placed it in a bag and spat in it.

From that classroom, you turned down a side corridor, past the changing rooms and into the sports hall. The smell of death that pervaded the school was most potent here. The majority of the dead hostages, about 330 in all, had been killed here. In some places the bodies had fallen in piles a metre high. The ceiling had collapsed, leaving only charred beams. Burnt wires hung here and there, where the terrorists had gaffer-taped them around the walls as they primed the sports hall to explode. A mixture of rain and debris had created a thick layer of sludge across the wooden floor of the gym. To walk through that room in the weeks afterwards was to walk on the dead.

If you stopped still, even for a moment, you could not help but visualise the stories you'd heard from survivors, the memories they couldn't forget. There, on the floor, was Aza Tsakhilova, aged 60, using her shoe as a cup to give her granddaughter Lisa sips of urine to quench her thirst, just before the explosions that killed Aza's pregnant daughter, Anna, and Anna's husband, Yuri, and rendered Lisa an orphan. The first day of the siege had been Lisa's first day at school.

Here was eight-year-old Mairbek Varziev, pleading with a terrorist to save his mother, Angela, offering the terrorist a five-rouble coin from his pocket (the equivalent of 10p), the terrorist saying: "I have plenty of money, I don't need yours." Mairbek's mother died there at the siege, while Mairbek was rescued by a soldier and is now receiving daily therapy.

Elsewhere in the sports hall was Larissa Sedakova, soothing her daughter Aida, watching another young girl, no more than 10, approach a terrorist and ask a question — perhaps she wanted a drink or to go to the loo, Larissa couldn't hear — and seeing the terrorist draw back and kick the girl so that she flew through the air across the room. When she closed her eyes afterwards, that was what Larissa saw, the girl in flight.

And there too was Lena Kasumova, the deputy director of the school, the mother of nine-year-old Timur, coming to after the first explosion, finding herself fallen on a piece of meat and thinking it must be a part of her, then realising it was all that was left of the woman who had been sitting next to her. It was, she said, like something out of a butcher's shop. Minutes later, Kasumova was running from the school with Timur in her arms, unaware that she was being photographed, conscious only that a woman running behind her had been shot and killed, realising that, for no reason at all, it was her destiny to survive, and the question of who lived and who died was random.

These were typical experiences, not by any means the worst or the most extreme (in all, for example, the siege created 24 orphans). This was simply how it was for the 1,200 teachers, parents and children in school No 1 in Beslan from September 1 to September 3, 2004. Over a quarter of those died; countless more were injured. All of those who escaped, and many who waited nearby, are now in varying stages of post-traumatic stress disorder. A psychologist working with them told me that many survivors from the sports hall have a common memory: shoeless as they escaped, they cannot forget the feel of the bodies beneath their bare feet. The people are in a state of shock. And, of course, terrible grief.

Beslan is a small, traditional community in the southern Russian republic of North Ossetia. No more than 40,000 people live there, all of them touched by the siege, everyone knowing someone who died or had been a hostage. In proportionate terms, you could say it was worse than the felling of the twin towers in New York three years ago. New York, in time, can perhaps absorb such a tragedy, but here in Beslan there is no escaping it. Here is a largely homogeneous population with common beliefs, mostly Orthodox Christians with extended families, a surprisingly comfortable place, given its rural location, with some poorer families but a high number of Mercedes-owners and private houses set back behind fortress-style gates. The wealth is mainly attributable to past enterprise in the vodka trade. So far, North Ossetians had been largely loyal to the Russian state and so were stable by comparison with their troubled neighbours in Chechnya and Ingushetia. The terrorists were led by Chechens pursuing their war of independence against Russia. It is now known that they had trained in and arrived from Ingushetia, which is unfortunate, as there has been long-standing hostility between the Ossetians and the Ingush, so old wounds have reopened.

You might imagine that the people of Beslan have been united by their tragedy, drawn together in shared pain and anger towards their common enemy, the terrorists and the Ingush. Instead, bitter divisions have opened up within the community. It is no exaggeration to say the town was being torn apart by suspicion, rumour and accusation during my visit there in November.

Everyone I met wanted to find out what had really happened. Who had enabled the terrorists to seize the school? Had the explosions on the third day that led to the fire and the chaos been triggered accidentally or deliberately, and if so, by whom? Why had so many people died? The constant plea was pravda, pravda — truth, truth — but it was also apparent that cynicism towards regional and federal politicians, from the North Ossetian president, Dzasokhov, all the way up to and including President Putin, was epidemic.