A document that appears to give the most powerful insight yet into how China determined the fate of hundreds of thousands of Muslims held in a network of internment camps has been seen by the BBC.
Listing the personal details of more than 3,000 individuals from the far western region of Xinjiang, it sets out in intricate detail the most intimate aspects of their daily lives.The painstaking records - made up of 137 pages of columns and rows - include how often people pray, how they dress, whom they contact and how their family members behave.
China denies any wrongdoing, saying it is combating terrorism and religious extremism.
The document is said to have come, at considerable personal risk, from the same source inside Xinjiang that leaked a batch of highly sensitive material published last year.
It contains details of the investigations into 311 main individuals, listing their backgrounds, religious habits, and relationships with many hundreds of relatives, neighbours and friends.