After American’s Killing in Syria, F.B.I. Builds War Crimes Case Against Top Officials

Mouaz Moustafa, the executive director of the Syrian Emergency Task Force, an advocacy group, said that an indictment would send an undeniable message. “No one should normalize relations with a regime that has killed an estimated 500,000 to a million people, including Americans and Europeans, and that continues to do so,” he said.

Asked to comment for this article or whether the F.B.I. had reached out, Ms. Shweikani’s father, Mohamed Shweikani, said, “I want nothing to do with running your story or the F.B.I.”

Spokeswomen for the Justice Department and the F.B.I. declined to comment.

As a child, Ms. Shweikani traveled to Syria to see family, and she earned a computer science degree in 2012 from Arab International University, according to her LinkedIn account. After working for a few years as a software engineer, she relocated in 2015 from suburban Chicago to Damascus to join a grass-roots network of humanitarian relief workers. But Mr. al-Assad tightly controls all official aid efforts in his country and he has treated citizen-run efforts as a threat, accusing them of terrorism.

By the time the authorities detained Ms. Shweikani on Feb. 19, 2016, along with her father and her fiancé, who were also in the country, almost every member of her relief group had been taken into Syrian custody. She would spend nearly a year in prisons on the outskirts of Damascus where cramped conditions, illness and torture run rampant: a detention facility at the Mezze airport, the Adra civilian prison and the Saydnaya military prison, where witnesses believe she was tried and executed.

Syrian guards tortured Ms. Shweikani, witnesses would later tell Justice Department investigators, recounting how they vowed to kill her father and fiancé, who had been detained for only a few days. The guards eventually forced her to falsely confess to crimes against the state, including terrorism.