Since the terrorist strikes of Sept. 11, 2001, an international dragnet has broken up training camps, disrupted finances, and sent terrorist leaders underground, making it all the more difficult for Al Qaeda to mount attacks.
But despite tougher border control, a radical ideology shared by the terrorist network continues to seep into the United States through propaganda distributed via the Internet, books, pamphlets, DVDs, and the media -- a ''passive recruiting strategy," according to specialists on terrorism. That has helped transform Al Qaeda into a movement with disciples acting without funding, expertise, or guidance of foreign handlers.
''Al Qaeda can't get their militants to the places they want to hit, so they rely on an ideology to gain converts who do it for them," said Brian Levin, a professor and terrorism researcher at California State University at San Bernardino.
In the Southern California case, prosecutors say cell members largely supported themselves.
Washington, Patterson, and Samana allegedly robbed gas stations to finance their plans to target military sites, synagogues, the Israeli Consulate, and the El Al airport counter in the Los Angeles area. Patterson purchased a .223-caliber rifle. Samana underwent ''firearms training and physical training" at a local park, according to the indictment.
They even conducted Internet research on potential targets and Jewish holidays -- dates they allegedly planned for the assaults to ''maximize the number of casualties," prosecutors said.
Samana's lawyer, Timothy Lannen, described his client in a statement as a ''peace-loving, law-abiding member of our community" who ''did not intend at any time to commit violence against anyone."
An attorney in Washington's state robbery case had not reviewed the federal indictment and had no immediate comment. Patterson's lawyer has said his client asked him not to comment.
The plot's suspected mastermind was James, an inmate at California State Prison in Sacramento who founded the radical group Jamiyyat Ul-Islam Is-Saheeh, authorities said. Washington converted to Islam while imprisoned there for a previous robbery conviction.
Self-made groups in the United States can be difficult to root out because they are smaller and have fewer financial resources to track, specialists said.
''They're adopting the Al Qaeda agenda and philosophy and carrying out their own jihad," said Buck Revell, a former FBI associate deputy director and counterterrorism chief. ''They may be successful because they're extremely hard to detect."