Noor's fate left his family, already struggling financially, in despair. His mother, Pashayam, 52, suffered a mental breakdown after his arrest; His father, Sherbaz Khan, 62, a Pakistani national, embarked on a non-stop series of trips between Pakistan and China, appealing for help in diplomatic circles and to the media. He was deported from China last month.

Above all, they still don't know what exactly Noor - their only son - did that evening that warranted such punishment.

'They said my son threw stones at a man who died later, but there were more than 30 men involved,' Khan told the South China Morning Post from Pakistan over the phone. 'Yes, my son might have made a mistake [participating in a riot]. But the allegations that he killed someone are baseless.'

Khan said Urumqi police had shown him on July 29 China Central Television footage of more than 30 people throwing stones at a man, but on June 17 this year, Aksu police showed him a video of just one person throwing stones. 'Why are there two different videos?' Khan questioned. In any event, he said the quality of the two videos were poor, and he could not recognise his son in either one.

Pashayam and Noor's grandmother, 76, attended Noor's trial in April, seeing the boy for the first time in nine months in the courtroom in Aksu, where the family has no connections at all. In fact, many July 5 trials were held outside Urumqi, a common practice in the mainland.

The two women were notified only two days before the trial, were escorted immediately to Aksu by government officials and were denied a meeting with Noor. The boy kept his head down throughout the trial, which lasted about an hour, and only once glanced at his mother and grandmother.

'They said my boy confessed to killing someone,' Noor's grandmother said. 'But I couldn't see him in the video. It was very small, and there were many people in it.'

Like many boys of his age, Noor was not great academically but showed talent in sport. On the evening of July 5, when he did not return home after sitting an exam that afternoon, Pashayam thought he was just playing soccer or basketball with friends. But he did not return that night or the night after.

Noor finally showed up on the third night. He reluctantly gave his mother a disjointed account of what happened: when he finished the exam that afternoon, an emotional procession of Uygur youths had marched past the school gate, calling for justice for two Uygur workers who had died 10 days before in a toy factory fight in Shaoguan , Guangdong. Exhilarated and under some peer pressure, he had joined the crowd. When he heard police were rounding up Uygur youths in the city centre, he went into hiding.

Pashayam recalled Noor repeatedly assuring her: 'I did not do things against your teachings. I did not steal things.'

The family is not well-off: Pashayam was a cashier at a state-owned department store before she retired early due to illness, and Khan, a small-time trader, was frequently on the road. But Pashayam is a proud woman, and she took Noor's education seriously. As a fluent Putonghua speaker, she made sure he grew up proficient in the Han language, and she was particularly proud when he became one of the few children in the Uygur neighborhoods to be accepted into a bilingual high school.

'How is it possible that he participated in the attack? He grew up among Han children!' the mother said.

Noor was arrested by police on the streets on July 27. Pashayam and Khan did not even know about it, until Noor's friends told them. And despite repeated visits to the police detention centre, they were barred from seeing the boy.

At the trial, the court appointed a Uygur-speaking defence lawyer, who appealed for a shorter sentence because of Noor's age, but nothing else. The family was not given a copy of the judgment after the trial, and there was no one to help them with an appeal.

'Pashayam filled out a form for appeal after she got back to Urumqi, but she did not know where or how to submit it,' Pashayam's sister, known only as Sha, said. 'I think she gave it to the officers from the local police station in the end. They said they would submit the appeal for her.'

Pashayam met this reporter in November in Urumqi and spoke on the phone several times; but her phone line has now been cut off because of non-payment. Pashayam used to pay frequent visits to Sha, who has been in a wheelchair since childhood, and her mother who lives one street away, but hasn't done so in more than a week due to sickness. Another of Pashayam's sisters keeps an eye on her.

'The whole family has been devastated by this incident,' Sha said, sobbing. 'Pashayam is pretty much bedridden, and my ageing mother is worried that she'll never see Noor again.'

Although the boy did not live with Sha and his grandmother, he often helped them with housework, knowing how difficult the job was for them. If he could not make it to their place that day, he would call. 'Just the day before he got taken away, he helped us cleaned our carpet,' the aunt said.

Noor does not fit the profile of the rioters as described by the government, either - that of young Uygur men from the poorer regions of southern Xinjiang, frustrated with unemployment, and incited by overseas separatist forces.

'The boy has always been well-behaved. We always taught him not to get into fights,' Sha said. 'If not for what happened that day [the protest], he would not have got into trouble.'

A piece of good news came to the family late last month: police told Pashayam that Noor had been transferred back to Urumqi. The family did not dare to ask for details; they were just thrilled to hear they might be able to see him, even if it was in prison.

Two months have passed, and the family has heard nothing from the courts about an appeal. A case registration employee at Aksu City Court said he could not provide information on a case without the name of judges involved, and no one answered calls at the criminal sub-court.

Sha said: 'We have always supported ethnic unity, and we'll continue to do so. We are just upset that our boy is so young and the punishment so harsh. We are lost about what to do now. We don't even know who we can ask.'

Noor's father Khan was banned from China for a year.

When he attempted to cross the border at Tashkorghan from Pakistan on June 9, he was detained for 10 days and then deported again. 'They say it's a punishment because I spoke badly about China,' Khan said. 'But I didn't. I am a good friend of China. I just wanted to save my son.'