The police officers came for Ayshem Mamut a week ago at her home in northwest China.

They told her to pack her bags. She could have been taken to a prison, a detention center or an internment camp, just like many other ethnic Uyghur Muslims who have vanished, sometimes for years.

But four days later, the 73-year-old Chinese citizen was in Virginia having a Thanksgiving meal with two sons she had not seen in 20 years and four grandchildren she had never met.

She sometimes talked, sometimes cried, as they ate traditional Uyghur dishes of noodle soup, lamb stew, broiled chicken, salad and rice with chickpeas.

Last week, U.S. officials said that China had freed three American men, one of them an F.B.I. informant, in exchange for two imprisoned Chinese spies and at least one other Chinese citizen. But as part of that deal, China also quietly agreed to allow Ms. Mamut and two other Uyghurs, one of them an American citizen, to leave the country for the United States.

The Biden administration has not made public the part of the deal involving the Uyghurs, and it is being reported here for the first time.

“Waking up in America and seeing my family, especially my grandchildren, is nothing short of a dream come true,” Ms. Mamut said.