dead? >> no. >> reporter: which is the greatest threat to u.s. national security right now? al qaeda in pakistan, al qaeda in yemen, al qaeda in north africa, or home grown terrorism? >> i would start with home grown terrorism. the most immediate threat is home grown terrorism as we've seen in the boston marathon. >> reporter: the threat connecting most home grown plots from the ft. hood massacre in 2009 to the boston marathon bombing is the followers of the first american targeted for death by the cia. >> the increase in individuals who are radicalized on the internet and in addition to that can gain the knowledge on how you develop an explosive device on the internet, that's the biggest threat at this juncture. after that al qaeda in the arabian peninsula out of yemen. >> reporter: fox's ongoing reporting of the cleric and newly declassified documents are raising questions over whether the u.s. government tried to recruit him as an intelligence source in 2002. >> i am not personally familiar with any effort to recruit anwar