What We Know About Abu Sayyaf: the Islamic State Leader Killed by U.S. Forces

Before Saturday, most Americans had never heard of Abu Sayyaf. But according to the Department of Defense, the senior Islamic State leader wielded the kind of power worthy of sending U.S. Special Operations forces into Eastern Syria on a rare and risky mission to capture him. That power, officials announced following the raid that ultimately killed Sayyaf, involved the major black market business fueling the Islamic State.