Mahmutjan Memetjan, 35, was picked up by authorities in 2017, the year authorities in the Xinjiang Uyghur Autonomous Region (XUAR) launched a vast network of internment camps that has incarcerated some 1.8 million Uyghurs and other Muslim minorities accused of harboring “strong religious views” and “politically incorrect” ideas, sources told Radio Free Asia.

The real estate investor, also known as Mehetjan Alqut, had lived in Yengisheher (in Chinese, Shule) county, in Kashgar (Kashi) prefecture, where he ran the Kashgar Alqut Property Company, reports RFA.

Chinese authorities have targeted and arrested numerous Uyghur businessmen, intellectuals, and cultural and religious figures in the XUAR for years as part of a campaign to monitor, control, and assimilate members of the minority group purportedly to prevent religious extremism and terrorist activities, the news portal reported.

Mahmutjan and other entrepreneurs went on a group business trip to the U.S. on April 8-22, 2016, source told RFA.

Since his detention and disappearance, Mahmutjan has been held in a “reeducation” or “training center,” China’s euphemistic terms for the XUAR internment camps, said an officer to RFA, who did not provide his name.

He told the news portal that he was unaware of the situation of Mahmutjan’s wife and children, including their U.S.-born daughter.