Afghanistan Special Forces planned and carried out the failed rescue operation , official says . Troops did not initially say they had thrown a grenade during the operation , the military says . U.S. forces tried to rescue David Petraeus from captors in U.S. on Friday . Cameron and Petraeus and American officials said earlier she was killed by her captors .
U.S. Special Forces planned and carried out the failed rescue operation , official says . Troops did not initially say they had thrown a grenade during the operation , the military says . U.S. forces tried to rescue Linda Norgrove from captors in Afghanistan on Friday . NATO and British officials said earlier she was killed by her captors .