ISIS Widow Charged in Kayla Mueller's Death Sayyaf was captured in raid that killed her husband By Rob Quinn, Newser Staff Posted Feb 9, 2016 1:27 AM CST Updated Feb 9, 2016 5:33 AM CST 38 comments Comments In this May 30, 2013, photo, Kayla Mueller is shown after speaking to a group in Prescott, Ariz. (AP Photo/The Daily Courier, Jo. L. Keener, File) (Newser) – The widow of an ISIS commander killed in an American raid last year could be spending the rest of her life in a US prison for her brutal mistreatment of American hostage Kayla Mueller and other captives, federal prosecutors say. Umm Sayyaf, a 25-year-old Iraqi woman captured in the raid that killed Abu Sayyaf, is accused of taking part in the kidnapping of Mueller, who was "owned" and sexually abused by ISIS leader Abu Bakr al-Baghdadi, NBC News reports. Federal prosecutors filed charges Monday against Sayyaf, who was transferred to Iraqi Kurdish custody a few months after her capture and is currently in prison in Iraq. Sayyaf has been charged with providing support to ISIS, which authorities say contributed to Mueller's death in ISIS custody. According to court papers, Sayyaf and her husband sold and traded women to ISIS fighters, and she was in charge of the captives when her husband was away. The court papers state that Sayyaf threatened to kill Mueller and two Yazidi women she was being held with, calling them "infidels" and showing them gruesome ISIS propaganda videos. Mueller died a year ago, and the Guardian reports that the court papers offer new details about her captivity. The 26-year-old was captured by ISIS fighters in August 2013, on her second day in Syria, and was kept in prison until September 2014, when she was turned over to the Sayyafs, according to federal investigators.