James Foley appears in video soon before his
James Foley appears in video soon before hisScreenshot

The US has identified the man behind the brutal decapitations of Western journalists James Foley, Steven Sotloff, and David Cawthorne Haines, FBI Director James Comey said Thursday.

Comey stated that the man, known informally as "Jihadi John" or "John of London," had been identified - but refused to name names. 

He did indicate, however, that the suspect was determined to have decapitated both Foley and Sotloff, based on evidence from their grisly death tapes.

In both tapes, "John" is shown wearing shapeless black clothing, with a black mask that leaves just slits for his eyes, and can be heard with a distinctive British accent. 

Linguistics experts determined recently that "John"'s London accent hides a different nationality, and that he was likely an immigrant. 

Experts also believe that "John" is the head negotiator in ransom talks for foreign captives in IS's territory in Raqqa, as well as the ringleader of a particularly brutal ring of British terrorists in IS known as the "Beatles," based on eyewitness accounts from other civilians held by ISIS for ransom.  

Previous suspects have been named as Abdel-Majed Abdel Bary, 23, a former rapper from Maida Vale, west London; former National Health Services (NHS) doctor, Shajul Islam; and Aine Davis, 30, from Hammersmith, west London.