russian authorities asked the fbi to investigate tamerlan, and in deciphering whether there were any problems with that follow-up, whether everything was done that needed to be done, help us understand how often does the fbi get requests like this, and what is the proper procedure for follow-up there? >> boy, that's a tough question but i think the answers to those questions are ones we need to know. the russian intelligence services approached the u.s. intelligence services, the fbi, with some information about tsarnaev, or at least a request that we, the u.s. intelligence officials, follow up with him. and the fbi did. they went through their due diligence. they interviewed tsarnaev along with his father and looked into what websites he was looking into and whatnot and decided he was not a person of danger at