Of those, 103 have become full investigations that have resulted in at least five arrests, the FBI said. There have been no convictions yet. An additional 365 reports have added information to ongoing cases.
But most remain in the uncertain middle, which is why within the FBI and other intelligence agencies there is much debate about the effectiveness of the bottom-up SAR approach, as well as concern over the privacy implications of retaining so much information on U.S. citizens and residents who have not been charged with anything.
The vast majority of terrorism leads in the United States originate from confidential FBI sources and from the bureau's collaboration with federal intelligence agencies, which mainly work overseas. Occasionally a stop by a local police officer has sparked an investigation. Evidence comes from targeted FBI surveillance and undercover operations, not from information and analysis generated by state fusion centers about people acting suspiciously.
"It's really resource-inefficient," said Philip Mudd, a 20-year CIA counterterrorism expert and a top FBI national security official until he retired nine months ago. "If I were to have a dialogue with the country about this . . . it would be about not only how we chase the unknowns, but do you want to do suspicious activity reports across the country? . . . Anyone who is not at least suspected of doing something criminal should not be in a database."
Charles Allen, a longtime senior CIA official who then led the DHS's intelligence office until 2009, said some senior people in the intelligence community are skeptical that SARs are an effective way to find terrorists. "It's more likely that other kinds of more focused efforts by local police will gain you the information that you need about extremist activities," he said.
The DHS can point to some successes: Last year the Colorado fusion center turned up information on Najibullah Zazi, an Afghan-born U.S. resident planning to bomb the New York subway system. In 2007, a Florida fusion center provided the vehicle ownership history used to identify and arrest an Egyptian student who later pleaded guilty to providing material support to terrorism, in this case transporting explosives.
"Ninety-nine percent doesn't pan out or lead to anything" said Richard Lambert Jr., the special agent in charge of the FBI's Knoxville office. "But we're happy to wade through these things."
Ramon Montijo has taught classes on terrorism and Islam to law enforcement officers all over the country.
"Alabama, Colorado, Vermont," said Montijo, a former Army Special Forces sergeant and Los Angeles Police Department investigator who is now a private security consultant. "California, Texas and Missouri," he continued.
What he tells them is always the same, he said: Most Muslims in the United States want to impose sharia law here.
"They want to make this world Islamic. The Islamic flag will fly over the White House - not on my watch!" he said. "My job is to wake up the public, and first, the first responders."
With so many local agencies around the country being asked to help catch terrorists, it often falls to sheriffs or state troopers to try to understand the world of terrorism. They aren't FBI agents, who have years of on-the-job and classroom training.
Instead, they are often people like Lacy Craig, who was a police dispatcher before she became an intelligence analyst at Idaho's fusion center, or the detectives in Minnesota, Michigan and Arkansas who can talk at length about the lineage of gangs or the signs of a crystal meth addict.
Now each of them is a go-to person on terrorism as well.
"The CIA used to train analysts forever before they graduated to be a real analyst," said Allen, the former top CIA and DHS official. "Today we take former law enforcement officers and we call them intelligence officers, and that's not right, because they have not received any training on intelligence analysis."