"Bernard Haykel" is Professor of Near Eastern Studies and the Director of the Institute for Transregional Study of the Contemporary Middle East, North Africa and Central Asia at Princeton University. He has been described as "the foremost secular authority on the Islamic State of Iraq and the Levant/Islamic State’s ideology."

Haykel, of "partially" Lebanese ancestry, grew up in Lebanon and in the United States.

More Bernard Haykel on Wikipedia.

It was akin to an animal being slaughtered, ... It was literally how you slaughter sheep. ...They slit the throat (at) the two carotid arteries, and they severed the head.

Being put on top of each other and forced to masturbate, being naked in front of each other — it's all a form of torture.