 -- In a new initiative, the FBI is trying to crowdsource the identities of U.S. citizens who have traveled or are planning to travel abroad to fight with terrorist groups, possibly including a North American-accented ISIS member seen in a video online preparing to execute prisoners.

“In the video, a man whose face is obscured by a mask alternates seamlessly between English and Arabic in pro-ISIL [ISIS] pronouncements intended to appeal to a Western audience,” a post on the FBI website today says, referring to an excerpt from a 55-minute-long ISIS propaganda video called “Flames of War”. “Dressed in desert camouflage and wearing a shoulder holster, the masked man can be seen standing in front of purported prisoners as they dig their own graves and then later presiding over their executions.”

The prisoners, the masked man claims in the video, are soldiers from the Syrian military in Raqqa.

The FBI notes the man appears to have a “North American” accent. After the “Flames of War” video emerged in mid-September, FBI Director James Comey told ABC News that investigating the man with the North American accent was a “big focus of ours.”

“The FBI needs your help identifying the individuals in this video as well as anyone traveling abroad to join terrorist groups,” said the FBI post, which also noted the FBI has set up a dedicated tipline at www.fbi.gov/ISILtips. ISIL, or the Islamic State of Iraq and the Levant, is the name the U.S. government prefers to use for the Iraqi terror group led by Abu Bakr al-Baghdadi that has taken over swaths of Iraq and Syria, whereas many news organizations, including ABC News, use ISIS for the Islamic State of Iraq and Syria.

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Top U.S. security officials estimate some 100 Americans have joined the fighting in Iraq and Syria on the side of various militant groups – around a dozen or so for ISIS, according to the FBI.

In addition to American recruits, the FBI has been working with its counterparts across the pond to identify another infamous masked ISIS member – the British-accented man who appears in the videos that purport to show the beheadings of Western hostages. Comey said last month the Bureau has identified that man.

CLICK HERE for more information on the FBI’s new push.