The man, who appears at around the 51-minute mark speaking in Arabic, seamlessly transitions to perfect English as men behind him dig with shovels. "We are here in the 17th division military base just outside the city of al-Raqqa and we're here with the soldiers of Bashar [al-Assad]," he says. "You can see them now digging their own graves in the very place where they were stationed."
This is the ending of the nearly one hour-long propaganda video "Flames of War," which is narrated entirely in English and meant for a western audience. After the unidentified fighter gives his speech, one of the soldiers condemns the Assad regime as others dig. The video then shows the group of soldiers being executed by the English-speaking man and other ISIS fighters.
While the video appears to show the execution of Syrian Army soldiers, Business Insider cannot independently verify that claim.
CNN Terrorism Analyst Paul Cruickshank offers some insight:
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."
Over at The Intercept, reporter Murtaza Hussain spoke with a linguistics professor, who said the man was probably not a native English speaker. However, based on this short clip of his speech, the professor believes his accent may hail from Minnesota, North Dakota, or even Canada.
CNN has video clips of the man: