The FBI announced Thursday that it has identified the man who appeared in the execution video of former UCF student Steven Sotloff.
FBI Director James Comey announced that the FBI believes it has identified the man, but that the Bureau is not releasing his identity to the public, according to a report from CNN.
Related: A tribute to Steven Sotloff
The man, officials say, appeared in all three execution videos released, including the murders of Sotloff, fellow American journalist James Foley and British aid worker David Haines.
The International Business Times reports that the Bureau has identified the militant after weeks of transatlantic intelligence efforts, and he is believed to be one of four British jihadists who have been tasked with overseeing ISIS hostages in Syria.
Although the militant has been identified, officials said that it's not possible to confirm that the man carried out the actual killings, as the murders aren't fully shown in the videos.
Sotloff, who was a UCF student from 2002-04, went missing more than a year ago while working as a journalist in Syria. He, along with Foley and Haines, were taken hostage by the terrorist group and used in videos to send a message to the United States, and other countries. All three hostages were beheaded in three separate videos.
Since then, the U.S. has engaged in air strikes on ISIS targets throughout Syria.