FBI Director James Comey said that U.S. officials have learned the identity of the masked ISIS terrorist seen on video beheading two journalists and an aid worker.
The executioner, which has been dubbed as "Jihadi John," spoke English with a British accent in the footage uploaded to the Internet by ISIS.
Comey, however, refused to reveal the name, nationality, or any other details regarding the true identity of Jihadi John.
"I believe that we have identified him," Comey said to reporters. "I'm not going to tell you who I believe it is."
The comments made by Comey come just a day after Philip Hammond, British Foreign Secretary, revealed that intelligence agencies were coming close to the identification of the masked executioner.
In the three videos where Jihadi John appeared, an ISIS militant brandishes a knife and begins slicing the throat of the hostage when the screen of the video fades out to black. Once the image of the video returns, the hostages have already been beheaded.
The three hostages that have been beheaded by Jihadi John are journalists James Foley and Steven Sotloff, both Americans, and aid worker David Haines, who is British.
Comey did not reveal if the U.S. officials have confirmed if the one that beheaded the hostages was actually Jihadi John, who is also believed to be the leader of a small group of British jihadis that are called by the hostages as The Beatles.
According to information gathered by intelligence agencies, around 500 jihadists from the United Kingdom are among the ISIS militants that are currently located in Iraq and Syria.
Comey added that about a dozen Americans are believed to be fighting with ISIS in Syria, with many more already having returned to the U.S.
Comey also said that the FBI is currently trying to determine the identities of two other men that were seen in the ISIS execution videos; they were able to speak English with apparently American accents.
"We have a big focus going on that right now," he said.
However, several British newspapers have already identified Jihadi John as Abdel-Majed Abdel Bary, 23, a failed rapper that left London and signed up with ISIS last year.
The two other individuals have also been identified by British newspapers as Razul Islam, 21, and Aine Davis, 30.
Comey added that the FBI believes ISIS is plotting something in the U.S., which Iraq's new prime minister Haider al-Abadi revealed as plans by ISIS to attack subways in the country and Paris, France.