URUMQI, China — She was one of the most revered academics from the Uighur ethnic minority in far western China. She had written extensively and lectured across China and the world to explain and celebrate Uighurs’ varied traditions. Her research was funded by Chinese government ministries and praised by other scholars.

Then she disappeared.

The academic, Rahile Dawut, 52, told a relative last December that she planned to travel to Beijing from Urumqi, the capital of the Xinjiang region where she taught. Professor Dawut was in a rush when she left, according to the relative, who spoke on condition of anonymity out of fear of punishment from the Chinese authorities.

She has not been heard from since, and her family and close friends are sure she was secretly detained as part of a severe clampdown on Uighurs, the largely Muslim group who call Xinjiang their homeland.