Orlando shooting: Did the FBI miss crucial warning signs?

As officials continue to look into Omar Mateen’s activities during the months leading up to the shooting at Pulse nightclub in Orlando, they are now looking into the two hours before the massacre when, authorities say, Mateen left the nightclub, then returned and opened fire. NBC’s Gabe Gutierrez reports for TODAY. (Run time: 2:40)June 22, 2016