What they described resembles a medieval reality show. Camera crews fan out across the caliphate every day, their ubiquitous presence distorting the events they purportedly document. Battle scenes and public beheadings are so scripted and staged that fighters and executioners often perform multiple takes and read their lines from cue cards.

Cameras, computers and other video equipment arrive in regular shipments from Turkey. They are delivered to a media division dominated by foreigners — including at least one American, according to those interviewed — whose production skills often stem from previous jobs they held at news channels or technology companies.

Senior media operatives are treated as “emirs” of equal rank to their military counterparts. They are directly involved in decisions on strategy and territory. They preside over hundreds of videographers, producers and editors who form a privileged, professional class with status, salaries and living arrangements that are the envy of ordinary fighters.

“It is a whole army of media personnel,” said Abu Abdullah al-Maghribi, a second defector who served in the Islamic State’s security ranks but had extensive involvement with its propaganda teams.