I believe the FBI is onto something here. Possibly learned from some loose lipped captives at Gitmo (Cuba).
Too late. Tampa teen kamimaze terrorist Charles Bishra/Bishop read Clancy novels and even lifted part of The Sum Of All Fears for his suicide note. He made a threat about a stolen nuke being used at the Super Bowl (which is why is note was not released for several weeks, conveniently after the Super Bowl).