FBI Pursuing Number of Strong Leads From ISIS Tip Line, Official Says

— -- A day after a public appeal for help, the FBI agents are aggressively pursuing a number of strong leads in the effort to track Americans who may have joined or are planning to join ISIS, a senior FBI official told ABC News, possibly including a man with a “North American” accent who appeared in a recent ISIS propaganda video presiding over the execution of prisoners.

“The FBI tips website that was announced yesterday has received a substantial number of web visits, some of which have generated leads,” another FBI official said earlier today. “We continue to call on the public to report suspicious activity of travelers in support of a terrorist organization or information about the subject speaking with a North American accent in the video issued by ISIL on September 19.”

Tuesday the FBI announced on its website it had established a new tip line devoted to information about U.S. persons who have joined or want to join ISIS, the Islamic State of Iraq and Syria, at www.fbi.gov/ISILtips. As referenced in the FBI statement today, in particular the Bureau wants to identify that man with the North American accent, featured in ISIS’s 55-minute-long “Flames of War” video from mid-September.

“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,” the web post Tuesday said. “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 FBI needs your help identifying the individuals in this video as well as anyone traveling abroad to join terrorist groups,” said the FBI post.

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

Earlier today FBI Director James Comey visited law enforcement officials in North Carolina, where he spoke frankly about this generation’s homeland threat.

“The growth of the internet, at the same time as the growth of these metastasized terrorist tumors, has created almost an industry where these groups seek to motivate and train people to do this work so that someone who’s never met a member of al Qaeda or ISIL [ISIS] in their pajamas in their basement gets all the motivation and all the training they need to engage in some kind of sick jihad here in the United States,” he said in a video published by The Charlotte Observer. “There are troubled souls everywhere in this great country of ours… So that remains an enormous focus for all of us in law enforcement.”

Brad Garrett, a former FBI special agent and a current ABC News consultant, said that the new tip line may not give the FBI the big break they need to catch major threats, they could provide longer term leads.

“The only thing that public requests tend to turn up is new information [like] ‘I have a neighbor that left. We haven’t seen him in three months.’ Or, ‘Somebody next door seems to be talking in jihadist lingo,’” Garrett said. “So those can lead to something, but by and large, they’re sort of long term leads that don’t really take immediate action.”

In addition to American recruits, the FBI has been working with its counterparts in Britain 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.