The plight of China’s Kazakh Muslims is little-known. But tens of thousands of them are locked up or missing in China’s Xinjiang province, alongside hundreds of thousands more Uyghurs. Now, whistle-blowers who worked inside mass detention units – so-called 're-education centres' - have revealed shocking accounts of ethnic Uyghur and Kazakh Muslims being subjected to horrifying abuse and systematic violence. Since 2014, Chinese authorities have been imprisoning Muslims in Xinjiang. Thousands of Kazakh muslims have been detained in 're-education' camps. Khalida Aqitqan's three sons are currently imprisoned: 'I don't know which prison they are in. I don't know if they are dead or alive'. Appalling treatment has been documented: 'There is evidence of mistreatment amounting to torture', says journalist Alison Killing.