American law enforcement officials believe roughly 250 Americans have tried to join ISIS, NBC News reported.
Assistant Attorney General John Carlin from the Justice Department told NBC News that his agency has investigations open in all 50 states.
While many of these Americans never leave the United States, a few dozen recruits have made the trip to join ISIS in Syria and Iraq.
Documents obtained by NBC News from a man claiming to be an ISIS defector identified at least 15 American citizens or residents who joined the terror group overseas — and they fit no particular pattern. Some are from poor Muslim immigrant families, while others come from what can be described as privileged backgrounds.
NBC News has a full list of names and background on the 15 Americans identified.