"The trend we're seeing is that we are uncovering more instances of people here who have been radicalized ... where there is not a direct thumbprint of al-Qaida," John Miller, an FBI spokesman, told USA Today.
Dozens of homegrown terror plots have been uncovered and prosecuted by federal and local authorities, the newspaper reported. While authorities originally were looking for U.S. groups with ties to al-Qaida, it's become clear that the groups often don't have ties to any international groups, USA Today reported.
Some of the accused plotters have undergone training overseas, some are born overseas and some are born in the United States.
"If they look like the neighbors next door, it's because that's what they are," Pasquale D'Amuro, a former FBI counter-terrorism chief and chief executive officer of Giuliani Security and Safety in New York told USA Today.