Ahmet S Yayla, Ph.D., Professor and former Chief of Counterterrorism & Operations Depart-ment for the Turkish National Police, is the Deputy Director of the International Center for Study of Violent Extremism (ICSVE) and the Adjunct Professor at the Department of Criminology, Law and Society at George Mason University (Washington). His last book is ISIS DEFECTORS. Inside Stories of the Terrorist Caliphate (2016), written with Anne Spekhard.