For nearly three years, CNN has been investigating allegations of gross human rights violations and a modern internment camp system in China's Xinjiang region.
The Asian country denies US accusations that Beijing detained up to two million members of the Uighur ethnic group and members of other minorities in internment camps.
For the first time, CNN has interviewed a former member of the Chinese security forces who says he was ordered to routinely arrest and torture Uighur detainees.
A warning to the audience: the report contains explicit descriptions of violence and sexual assault.
CNN Exclusive: "Some are just psychopaths": Chinese detective in exile reveals scale of torture against Uighurs.