Who is the English speaker in ISIS video ‘Flames of War’?

It’s a slick production with a nefarious goal: A 55-minute video released by ISIS, praising its victories and warning the United States from getting in the way of its goal to create an Islamic caliphate in parts of Iraq and Syria.

It’s propaganda, terrorism experts say. A recruitment video aimed at English speakers.

But the U.S. intelligence community is focused on one jihadist who appears briefly at the end of the video. The ISIS fighter, who speaks perfect English with a North American accent, is shown orchestrating the mass execution of a group of men.

It is too early to know if this militant hails from North America, or maybe spent some time there, or what his exact story might be.

But the intelligence community is already analyzing the video in an attempt to identify the man’s origin, a U.S. official told CNN. It is too early to tell where his dialect is from, the official said.

In the video titled “Flames of War,” the jihadist first appears speaking Arabic in a classical dialect and with the ease of a native Arabic speaker, CNN terrorism analyst Paul Cruickshank said.

But the ISIS fighter – who is masked and wearing a camouflage uniform – seamlessly switches to English. There are a number of men digging a ditch behind him. The jihadist claims they are Syrian soldiers assigned to a 17th Division military base near the Syrian city of Raqqa, and who now, after an ISIS attack, are “digging their own graves in the very place where they were stationed.”

CNN cannot independently verify that the men in the video were soldiers, as the propaganda video claims.

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The video then shows a group of militants executing the men, who fall into the ditch.

The man who committed this atrocity on film could be an Arab who was educated in the West. Or he could be an American or Canadian. If so, Cruickshank said, he would be the first North American jihadist to commit a war crime on camera.

“Clearly ISIS had a calculated step to be able to put this guy on camera,” said Frank Cilluffo, a security analyst at George Washington University. “Why? Because he seems American. The message is aimed at a Western audience.”

The intent, Cilluffo told CNN, is to project fear to Americans, and to project power.

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Intelligence officials will sift through every detail of the man’s voice, looking for any clues of a particular dialect that might lead investigators to local communities to seek additional clues, Cilluffo said.

The U.S. will also compare the clues of the jihadist’s language to see whether it is consistent with those individuals who are known to have gone to fight for ISIS.

The video is undoubtedly propaganda and a recruitment piece for the terrorist group, Cruickshank said. But it is also a warning to the West that if it gets involved in the fight, it will be a tough outing for foreign troops.

The video doesn’t exactly goad the United States and the West into launching attacks against ISIS, but those who appear in the video try to convey a sense of toughness, Cruickshank said.

The video glamorizes ISIS, according to SITE Intelligence, which monitors terrorist groups.

“It serves as not only a powerful recruitment piece, but a stern warning to their opposition about ‘flames of war’ rising against them by the fighters,” according to a summary by SITE.

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CNN’s Pamela Brown contributed to this report.