Attention in the U.K. has honed in on "Jihadi John" Abdel-Majed Abdel Bary, a 23-year-old British-born rapper who flew to Syria several months ago. He is the son of alleged al-Qaida mastermind Adel Abdul Bary, 53, who was extradited to the U.S. last year and is accused of planning the bombings of U.S. embassies in Africa in 1998.
But experts analyzing the video believe the execution may have been staged for the video, speculating the mask-clad speaker and the executioner are actually two different people.
An unnamed international forensic science company, conducting analysis for the The Times in London, noticed a "blip" in the footage indicating Foley may have had to repeat portions of a scripted statement, later edited together using "slick post-production techniques."
The expert said the video shows no blood on Foley's neck as the knife was drawn across his neck at least six times.
"I think it has been staged," one of the forensic experts told the news organization. "My feeling is that the execution may have happened after the camera was stopped."
Ross Patel, a forensics expert, told CNN there were "noticeable changes in their build, their physical appearance" between the speaker and the apparent actual executioner. The knife held by the speaker appears to be different than the one left next to Foley's body, and while the speaker has his pistol holstered on his left side -- indicating right-handedness -- the executioner appears to be left-handed.
The Islamic State is believed to have kidnapped Foley near the Turkey-Syria border nearly two years ago, reportedly holds a number of Western hostages.
The group, formerly associated with al-Qaida, has taken over large swaths of Iraq and has become Bashar al-Assad's principle antagonist in Syria.
In the week since Foley's death, another IS video has surfaced showing the execution of an Iraqi soldier, with the video in Arabic. The Foley video was in English and conducted by an executioner experts believe is British, a deliberate message to the U.S. and Great Britain.
U.S. federal investigators also believe they have identified the social media account used to post the video, a "key part of the forensic" trail that would lead to Foley's killers.
They say the account belongs to a jihadist who is part of a group close to IS leadership and regularly posts images of the leadership's activities. A counterterrorism analyst told Fox News the account's proximity to IS leadership likely means Foley's kidnapping and execution likely came at the behest, or with the approval, of top IS brass.
Media learning of the name of the account have been asked not to publish it, to avoid tipping off its owner. Many within the group are already moving away from their regular social media patterns to evade detection.