EYES downcast, head bowed, Nurpashi Kulayev walked into the courtroom to face boys and girls whose school friends he is accused of killing.

Mr Kulayev, who was the only hostage-taker captured after the Beslan school siege a year ago, watched impassively as one 14-year-old boy broke down on the witness stand.

“Give this terrorist to us! We will tear the bastard apart!” shouted one woman as relatives packed the room.

This trial in Vladikavkaz, the regional capital, was supposed to bring a sense of justice and closure to the families of the 330 people, 186 of them children, killed on September 3, 2004. Instead it has fuelled their fury that Mr Kulayev, 25, a Chechen carpenter who admits being a hostage-taker, but denies killing anyone, is alone in the dock.

Many would rather see on trial the senior officials who, they say, are responsible for allowing the terrorists to take the school on September 1, and then botching the rescue. Susanna Dudiyeva, the head of the Beslan mothers’ committee, said: “It is obvious that Kulayev will be found guilty. What we want is to see the responsible government officials on trial.”

Mrs Dudiyeva, who lost her 13-year-old son, Zaurbek, in the siege, stunned the court in June when she proposed that Mr Kulayev be offered a pardon if he told the truth.

This week she and a dozen other mothers took over the courtroom for 24 hours, demanding to meet Nikolai Shepal, the prosecutor leading the investigation. When he failed to appear, they said that they would boycott the trial.

Mr Shepel, the Russian Deputy Prosecutor General, said that his investigation would go ahead as planned and that officials would eventually be prosecuted. "We cannot simplify the case just because the mothers’ committee insists on that," he told The Times. "As a prosecutor I cannot be governed by emotions. The investigation must be based upon facts which are proven."

The problem, critics say, is that neither Mr Shepel nor the federal parliamentary commission investigating the siege appear willing to accept evidence contradicting the official version of events.

When several witnesses said that there were more than 32 hostage-takers, Mr Shepel took a vehicle like the one that the hostage-takers used, and packed in 32 Russian soldiers with weapons and ammunition. It could not fit any more.

“That’s enough for us,” said Sergei Trokopov, Mr Shepel’s press secretary.

Investigators have given similarly short shrift to evidence contradicting the official line that the storming began when the terrorists set off a bomb.

Fatima Dudiyeva, a police major who was among the hostages, testified that she was shot through the hand shortly before the first explosion, backing Mr Kulayev’s claim that a sniper shot a terrorist whose foot was on a trigger pedal. She has a medical report diagnosing her injury as a bullet wound. Mr Shepel, however, insisted that it was caused by shrapnel and that the man on the pedal would have been invisible to a sniper. “They’re hiding everything,” said Mrs Dudiyeva, whose nephew died. She was clearly traumatised. Nevertheless, a quick look at the sports hall showed that the terrorist on the pedal would, in theory, have been visible from a nearby apartment block.

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