FBI Director James Comey revealed he knows which Americans have joined the Islamic StateAbout "a dozen or so" Americans have joined the terror organization, but there is a possibility there are more, Comey said in an interview with “60 Minutes” aired Sunday. He said he will keep a watchful eye on those who have joined ISIS, the militant group formerly known as the ISIS and ISIL, especially if they return to the United States. 

"Ultimately, an American citizen, unless their passport is revoked, is entitled to come back," he said. "So someone who has fought with ISIL, with an American passport, wants to come back, we will track them very carefully."

The terrorist networks in Syria are a "metastasis of al Qaeda," especially al-Nusra Front and ISIS. "They are both vicious,  sort of the inheritors of a lot of the mantle of al Qaeda and present different threats in a lot of ways," he said, according to Fox News.

Dangerous as they may be, the U.S. is not threatened in the same way it was when al Qaeda was at its peak. "We’re better organized and equipped at the border," he said. "We have relationships with our foreign partners. All of which make us better able to see dots and connect dots," Comey said. "The transformation since before 9/11 is striking." 

On another topic, the FBI director said Americans are not very aware of threat posed by cybercrime. One of his main goals as director of the FBI, he said, is to cut down on cybercrimes like identity theft and industrial espionage.

Follow me on Twitter @mariamzzarella