welcome back to the lead. i'm jake tapper. is he dead or alive? that saturday question american defense officials are trying to answer about one of the most wanted terrorists in the world. a master bombmaker with ties to the khorasan terrorist group in syria which is believed to have been killed in a u.s. airstrike, but now there are some doubts about that claim. cnn's pentagon correspondent barbara starr is here with details on this breaking story. barbara? >> hi, jake. david drujan, french man, master bombmaker of the khorasan group from pakistan to syria a number of years ago. the u.s. had hoped they had got him in a november air strike. now two u.s. officials telling me every reason to believe he is still alive and a big concern to the u.s. because of his bomb making skills. they are continuing to monitor