to be a double agent, instead of boarding a u.s.-bound plane, he turned it over to the cia. randall pinkston reports from washington. reporter: the double average who helped foil the plot, also helped the u.s. take out one of its terrorist group leaders. according to officials, he gave the u.s. information that led to last week s drone strike against fad alcousteau. al qaeda s chief officer in yemen. but there is no indication that they have gotten any closer to the bomb-making mastermind. when does the bomb-maker go down? my question here wouldn t be simply, did we or didn t we stop the plot? my question would be, did we get enough information to stop the bomber. and that s the average still in the field. reporter: he removed himself from the operation, and cost himself a valuable cia asset. when you re watching this threat develop, have a you have a simple priority. and that is to ensure, even if you want to destroy the organization, you don t put others at risk.