The video, titled “Though the Unbelievers Despise It”, was released on Nov. 16 and runs for close to 16 minutes. It was choreographed to show the simultaneous beheading of the hostages by 22 ISIS executioners, as well as the murder of U.S. aid worker Peter Kassig.

Analysts at the U.S.-based Terrorism Research and Analysis Consortium (TRAC) and the U.K.-based Quilliam Foundation discovered lighting and shadows that reveal the video was shot in multiple takes over a period of several hours. The line-up order of the killers and prisoners is switched and in certain frames fighters chat with one another as if idly passing time between takes.

Virtually all the killers — of varying ethnicities and nationalities — are unmasked and potentially identifiable, although only one has been identified: Maxime Hauchard, a French convert to Islam. The killers are led by the figure known as “Jihadi John,” the masked British militant believed to be responsible for the beheadings of James Foley, Steven Sotloff, David Haines, Alan Henning, Peter Kassig and two unidentified Syrian soldiers.

Veryan Khan, a researcher with TRAC has been analysing the video frame-by-frame. She says the video would have had a director, producer and editor who may even have used storyboards like conventional film-makers. The video was likely produced using Avid Technology, a state-of-the-art program which costs at least $200,000.

Khan says the executioners were chosen for their cinematic qualities, their appearance and their martial ability. She points out that the men represent a certain kind of aesthetic; they are rather good-looking, clean and look as if they’ve done this before. The fact that they come from across the world is intended to convey the broad reach of ISIS’s self-proclaimed caliphate, Khan adds.

The researchers believe the video was aimed at supporters, potential recruits, enemies and also the ISIS leader, Abu Bakr al-Baghdadi. In a statement, the researchers suggested the fighters were probably willing participants because they would “enjoy international infamy, transforming them into social media heroes like ‘Jihadi John’ and rendering them valuable assets for future propaganda. Already countless [ISIS] Twitter supporters are using the executioners’ photos as their avatars.”

The analysts also say the executioners cleaned themselves up between the filming of execution and post-execution scenes, another indication of the work involved in producing the film.

ISIS’s media approach is central to propagating the message that it is unstoppable, Khan says. But while the work is professional, the analysts have noticed tell-tale inconsistencies within the footage that hint at the forensic footprint of a specific editor. Tracing this signature will, they hope, eventually lead to the identification of key figures possibly at the highest levels of the ISIS hierarchy – something which may just prove crucial in the fight still ongoing in Iraq and Syria.