nearly half of the people are federal employees at the high hours the second threat in 9 past couple of months. in october the f.b.i. arrested a man who thought he was working with members of al qaeda to attack the subway stations. and now, with the news from washington, dc. were they threats? or was it a real plot? >> according to the criminal complaint, the individual in question is charged with making threats over the internet. he is not charged specifically with a plot against the washington, dc metro system. there are two or three components to the threats. the pipe bombs. he talk about maximizing the bombs and what cars would be the best spots for the pipe bombs to have maximum casualty. but these are threats not part of a specific plot. >>shepard: did he think someone tipped off the f.b.i.?