no one knew when gulgine would be released. >> (gulzire): >> (gulgine): >> (gulzire): narrator: during built around 1,200 detention camps that held an estimated two million uyghurs and other muslims-- what experts have described as the largest mass incarceration of an ethnic group since the holocaust. ♪ >> (gulzire): >> narrator: back in xinjiang, our undercer colleague, li, is trying to find people willing to talk about the camps. a week into his trip, he has ati chance m with a uyghur who speaks english. but he's afraid to speak openly. >> narrator: li discoverthat this uyghur man's parents have been sent to a camp. >> (reporter): >> narrator: china has tried to portray the camps in a positive light. >> (woman): >> (announcer): >> (group): >> (woman 2): >> (announcer): >> (woman 3): >> (man): >> (all): >> (woman): n rator: but classified chinese government documents obtained by the international consortium of investigative journalists reveal a much different picture of life inside the camps. the documents depict the camps as involuntary indoctrinatn centers with high watchtowers, ,ns