When Ziba Murat last saw her mother, retired Uyghur doctor Gulshan Abbas, at Ronald Reagan Washington National airport in 2016, she begged her not to return to Xinjiang, where reports were emerging about the detention of ethnic minorities.

"My heart started to beat so fast. I told her not to go," said Murat. "We had already started to hear about the camps being built, but she thought she was safe."

Shortly after returning home, Abbas told her daughter that her passport was confiscated, without providing details. Murat said their daily video calls became tense, and at times, Abbas would shake her head and cry for no apparent reason.