Thus far, the executioner has been known only as "Jihadi John." He was known to intelligence officials as a hostage negotiator for a group of British ISIS fighters in Syria. He was also a guard for hostages in Raqqa. He originally hails from the United Kingdom, likely the London area, based on his accent. One of his former hostages said John is "intelligent, educated and a devout believer in radical Islamic teachings."
While the identity is now known to intelligence officials, it will not be publicly released, presumably as the military works to apprehend him. Though the man will not be named, this is a major step to taking down the terrorist network.
Yesterday, a "copy cat" video of the ISIS beheadings was released by the terrorist organization "Caliphate Soldiers" based in Syria. They murdered a French mountaineer who was kidnapped in Algeria, though their video was distinctly different than that of ISIS, in which "John" is featured and gives the final speech in English.
Earlier this week, ISIS released a propaganda video featuring another hostage, John Cantlie, in which he reads a script denouncing the Western media and airstrikes against ISIS occupied territory. This is the third ISIS propaganda video released this week, the second being another Cantlie monologue, and the first a movie trailer style recruitment video. None of those videos featured the now identified executioner.