One October night in 2017, Sayragul Sauytbay received a call from an unknown number. She was ordered to go to a special place and was asked not to ask questions. If she didn't sound, the consequences would be serious. Sayragul chose to obey.

In an interview with SVT, she describes how she was taken to one of China's notorious detention camps in Xinjiang Province - Sayragul calls them concentration camps.

- Each person had one square meter of space to sleep on. They had to lie on the right side, if they moved, they were punished.

Sayragul Sauytbay had worked as a principal in his hometown and was forced to act as a teacher for the "students" who were in the camp. In practice, they were all prisoners.

A leaked document shows how the detention camps in Xinjiang Province function as prisons where prisoners - mainly Muslim minority groups - are forced to learn loyalty to the central government in Beijing.

SVT Nyheter is one of 18 media that participated in an international review, coordinated by the journalist network ICIJ. Other contributors include the British BBC and the German Süddeutsche Zeitung. The document has been shared between participants and the review has been under the name #ChinaCables.

READ MORE: Here is the document in detail

The document is dated June 2017 and is believed to have been signed by Xinjiang's deputy party secretary. It is addressed to the camp managers and reproduces a series of restrictive measures for the inmates - not least monitoring, even during toilet visits.

It also states that they are not allowed to have cell phones or contact with the outside world, except on selected occasions.

According to Sayragul Sauytbay, much of the so-called teaching was about teaching Chinese traditions and the principles of the Chinese Communist Party.

The document also contains instructions which say that the prisoners should investigate themselves and be asked to "acknowledge past sins".

- It was called self-reflection, says Sayragul Sauytbay.

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Scoring system for prisoners

The document prompts camp managers to set up scoring systems to evaluate students' ideological transformation, their studies, and their ability to follow rules.

"Link the score directly to rewards, punishments and family visits," it says in a passage further down.

Another paragraph states that the inmates can only be released after one year, if they achieve certain set goals.

China denies

Chinese representatives believe the document to be false.

"Don't listen to fake news," said China's London ambassador Liu Xiaoming when confronted with the issue by the BBC's reporter.

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However, several leading experts on the situation in Xinjiang believe that the document is likely to be authentic.

Sayragul Sauytbay says that she was beaten with rubber batons and witnessed how a prisoner was used sexually by camp guards before the eyes of other prisoners.

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In March 2018, five months after she was taken to the camp, she was driven home again. A short time later, she fled to neighboring Kazakhstan, where her husband and children were already located. But the family still did not feel safe and took refuge in Europe.

- It wasn't until I came to Sweden that I could feel that my children and I were safe, says Sayragul Sauytbay.