The FBI is asking the public to help identify an English-speaking man who purportedly presided over prisoner executions in an ISIS propaganda video.

In the video, released on Sept. 19, the man easily switches between Arabic and English with a North American accent.

, in hopes that someone will recognize the man’s voice or appearance.

The man in the video is shown wearing camouflage, with a black mask obscuring his face.

He can be seen standing in front of several men who are shovelling dirt. He says the men are Syrian prisoners who are digging their own graves. Later, he appears to orchestrate their executions. 

“We’re hoping that someone might recognize this individual and provide us with key pieces of information,†Michael Steinbach, assistant director of the FBI’s Counterterrorism Division, said in a statement. “No piece of information is too small.â€

The FBI is also asking people to come forward with information about anyone who has travelled, or is planning to travel, overseas to join terrorist organizations.