WASHINGTON (WUSA9) -- The beheading of a U.S. Journalist by ISIS, University of Maryland researcher Phillip Smyth says, could be a precursor of what's to come.
"The unknown certainly plays into it, kind of playing off of this fear and really brutality of beheading somebody" Smyth says.
And there's legitimate fear ISIS terrorists could strike the homeland.
There have been reports of a small group of Americans who have joined ISIS, positively identified by the US government. More than a thousand Western Europeans have joined ISIS as well.
Since June there has been an increase in the social media techniques and tactics used by ISIS to persuade and recruit, in particular its active use of twitter.
"They understand that this is a medium that they can utilize that's free. They can have a good level of operational security because I can start an email account and start putting up different pieces of information" Smythe explained.
There's been a backlash as well, the hashtag #ISISMEDIABLACKOUT has gained steam as Twitter users urge others not to share the video of James Foley, or any other graphic images released by the militant group.
ISIS has captured attention because of that social media campaign and the unthinkable act it committed when it beheaded James Foley, but Smythe says the terrorism front is so much bigger than ISIS:
"This is not just one problem. We keep concentrating on something has a name factor, name recognition, but there are many other militant groups sometimes those opposing the Islamic state ISIS, which also hate the United States and want to fight us, and also use social media, and also use brutal tactics."