Shootings In Chattanooga: What We Know About The Alleged Gunman

A day after a gunman opened fire at two military centers in Chattanooga, Tenn., and killed four Marines, authorities are trying to answer the big question: Why?

At a late-night press conference, authorities said they had yet to pin down a motive. But earlier, officials identified the shooter as 24-year-old Mohammod Youssuf Abdulazeez, who died during the course of the attack.