The number of homegrown violent extremist cases continues to rise, posing a challenge for the FBI. In just the last two weeks, federal prosecutors have charged seven people in terrorism cases.
Andrew McCabe, the head of the FBI's Washington field office, is concerned about the FBI's ability to track every potential homegrown terrorist.
"It's not hard to anticipate that, as numbers begin to grow, at some point our traditional investigative approaches and capabilities will be outstripped by the sheer numbers we're facing," said McCabe.
Many cases are time-consuming and involve lengthy undercover work. When prosecutors announced charges last week against two New York women, it was the culmination of a nearly two year investigation.
The group is enticing middle school and high school aged students to sympathize with its cause or even travel to Syria to join the fight.
McCabe wouldn't specify exactly how young some of the recruits are, but said they've seen several cases of children in their "early and mid-teens" attempting to travel overseas.
McCabe believes the FBI has to broaden its reach by engaging even more with local police, local mosques, community leaders and parents to counter the ISIS message. It's an approach similar to what law enforcement has used to combat gangs in America's cities.