A key disclosure in the leaked directive is an official description of the conditions that detainees must meet to be released from the camps. Aside from achieving a good score in the point system, the document said, inmates must be categorized at the lowest threat level and have served a minimum term of one year — though interviews with former detainees indicate that camps sometimes release people sooner.

The directive also emphasized the importance of showing remorse. Discussions with detainees should “promote the repentance and confession of the students for them to understand deeply the illegal, criminal and dangerous nature of their past behavior,” it said.

A different document, among the set shared with The Times earlier this year, described how family members outside the camps are told that their behavior can also affect when a detainee is released — a implied threat aimed at silencing complaints.

Former detainees said the criteria for release seemed arbitrary, and there was little clarity on when or why people could leave.

“You enter the camp with 1,000 points. You can’t gain points. You can only lose them if you yawn or smile,” recalled Rahima Senbai, who was held in a camp in October 2017 and only allowed to return to her home in Kazakhstan a year later. “If you ever went under 500 points, you’d have to stay for another year.”

Zharqynbek Otan, who was held in a camp for seven months after his arrest in January 2017 and has since fled China, said the goal of the detention was to impose loyalty to the Chinese state.

“The main purpose is to brainwash you,” he said, “so you forget your roots and everything about Islam and ethnic identity.”