The conditions laid out by the Islamist are strict: no photos and no audio recording. He also keeps his real name secret as well as his country of origin, and is only willing to disclose that he is Arab. His English is polished and he speaks with a British accent.

He calls himself Abu Sattar, appears to be around 30 years old and wears a thick, black beard that reaches down to his chest. His top lip is shaved as is his head and he wears a black robe that stretches all the way to the floor. He keeps a copy of the Koran, carefully wrapped in black cloth, in his black leather bag.

Abu Sattar recruits fighters for the terrorist militia Islamic State in Turkey. Radical Islamists travel to Turkey from all over the world to join the "holy war" in Iraq or Syria and Abu Sattar...