The Islamic State of Iraq and Syria's "Grand Mufti" or chief cleric, Turki al-Bin'ali, was killed in a U.S.-led coalition airstrike last month in Syria, Fox News reports.
Al-Bin'ali appeared in numerous ISIS propaganda videos as one of the group's most visible preachers, and was sanctioned by the U.S. for helping recruit foreign fighters.
He also wrote a biography of ISIS leader Abu Bakr al-Baghdadi.
Al-Bin'ali was killed on May 31 in an airstrike on Mayadin, Syria, according to the Combined Joint Task Force — Operation Inherent Resolve.