unknown factor. we know more about him, but there are others who maybe they were waiting their turn to rise to prominence, and now that bin laden's gone, they'll step up, and we'll see what they're capable of. jon: ray locker is managing director of the project on terrorism. thanks. jenna: a startling new twist on a murder mystery we've been following closely, police on long island identifying a tenth victim. why they now believe there's more than one killer on the loose. also, new weapons that could redefine warfare. how u.s. troops armed with smartphones are reshaping the the fight on the battlefield. we have both of those stories straight ahead for you. okay, team! after age 40, we can start losing muscle --