Rick Friedman-Pool/Getty Images
EDGARTOWN, MA - AUGUST 20: (AFP OUT) U.S. President Barack Obama makes a statement about the execution of American journalist James Foley by ISIS terrorists in Iraq during a press briefing at the press filing center at the Edgartown School August 20, 2014 in Edgartown, Martha's Vineyard, Massachusetts. A video released shows an ISIS militant beheading Foley in what is believed to be retaliation for U.S. airstrikes in Iraq. The militant then threatens the life of another American hostage, Steven Sotloff, who is also missing. (Photo by Rick Friedman-Pool/Getty Images)
The killing of American journalist James Foley by Islamic militants in Syria this week has sparked widespread outrage. It's also renewed concerns about the jihadi fighters' ability to recruit foreigners, including Europeans and Americans. The killer in the video posted online is a masked, English-speaking man with a British accent.
Colin Clarke, an associate political scientist with the RAND Corporation, explains the recruiting tactics of the group, which calls itself the Islamic State.