The widow of a former ISIS leader is charged in connection with the abduction of former Prescott humanitarian worker Kayla Mueller. Federal prosecutors filed charges Monday against 25-year-old Iraqi Nisreen Assad Ibrahim Bahar, also known as Umm Sayyaf. She was married to Abu Sayyaf, the senior ISIS leader who was killed last May by U.S. forces. The Justice Department says Sayyaf is in custody in Iraq for terrorism-related activities. Prosecutors say Umm Sayyaf threatened Mueller and two other women who were being held. The FBI says Mueller was sexually assaulted by another ISIS leader and Umm Sayyaf knew what was going on. Mueller was kidnapped in Syria in 2013. She was reportedly killed in a Jordanian air strike a year ago this past Saturday. Mueller attended Tri-City College Prep in Prescott and is a graduate of NAU.