hersh says somebody within pakistani intelligence walked into the u.s. embassy and said i know where he is. cnn sources aren't ruling out that at some point somebody walked in and did give some kind of information that may have been helpful. but they insist it was not one person or one piece of evidence that cracked open this case. alisyn. >> okay michelle thanks so much for that. we'll talk about it much more in the program. meanwhile, a stern warning from the director of the nsa, isis is increasing its already successful efforts to spread its message on social media and it's apparently resonating with more americans. cnn's senior correspondent nick paton walsh has more for us. nick. >> reporter: well this morning morning -- after texas shootings were claimed by isis but beforehand shooters pledged alee yans -- allegiance.