workers killed bay drone strike in pakistan. it happened in january. we learn more about it from u.s. security correspondent jim sciutto. >> reporter: it was in this mountainous border region between pakistan and afghanistan that a u.s. drone strike killed two western hostages held by al qaeda, including one american, warren weinstein, abducted in pakistan in 2011. al qaeda compounded been under surveillance for hundreds of hours. what the u.s. did not know it is that weinstein and giovanni were held and hidden inside. in this proof of life video, weinstein, an aide worker, pleaded for his freedom. >> it seems i have been totally abandoned. >> today president obama apologized for a fatal mistake. >> we believed that this was an al qaeda compound. that no civilians were present and capturing them were not