The identity of the Islamic State (IS) militant "Jihadi John" who executed two American journalists has been determined and will be revealed within days, according to British and American authorities.

The Guardian has reported that a U.S. intelligence source has assured that the identity of the IS (previously referred to as ISIS/ISIL) will be officially made public within the next few days.

Jihadi John has been deemed as the executioner behind the decapitation of journalists John Foley and Steven Sotloff; he has also allegedly made threats to kill an aid worker from the U.K. named David Haines. Authorities are now figuring out the next step in an attempt to allow Haines, who the IS militant in the video claimed is next for execution, to gain freedom.

According to the latest report of The Independent, sources have stated that anti-terror authorities from the FBI have been sent to Britain last August to identify and move in towards at least 12 suspects reportedly keeping cover in the U.K. These individuals are believed to have given financial aid along with the necessary contacts for Jihadi John to be able to fly into Syria.

Among them are a number of West Midlands residents who have already been identified by U.K. security services. Intelligence officers are said to be regularly monitoring all communications and transactions of these suspects who are believed to have been of assistance to Jihadi John.

As the US insider specifically claimed: "It has been a co-ordinated effort to track down the support network around the British Islamic State executioner. Our inquiries have given us leads across the country. We are 99.9 percent certain now as to who 'John' is but investigators have had to tread softly in charting and approaching his wider network in the UK."

Jihadi John is only one of the four jihadists from the U.K., referring to themselves as the "Beatles," who have held and executed hostages in Syria. The other three have reportedly been identified also by the American and British authorities.

Facial recognition techniques have been the key approach to identifying the hostage executioner, particularly with the use of his eyes that was exposed in the beheading video released last month. While the first footage showed the gruesome execution of James Foley, another video followed showing fellow hostage Steven Sotloff being decapitated only last week.