The wife of a senior Islamic State leader who was killed in a U.S. raid last year has been charged in federal court with holding American Kayla Mueller hostage and with contributing to the aid worker’s death, the Justice Department said Monday.

Nisreen Assad Ibrahim Bahar, also known as Umm Sayyaf, admitted after her capture last May that she and her husband kept Mueller captive along with several other young female hostages, according to an FBI affidavit filed in the case. U.S. officials have said that while in custody, Mueller was repeatedly forced to have sex with Abu Bakr al-Baghdadi, the leader of the Islamic State group.