comcast, building america's largest gig-speed network. there is outrage in east pittsburgh today. a police officer shot and killed an unarmed teenager just hours after the officer joined the force and was sworn in. investigors say was shot three times from behind. he had just jumped out of a car that police pulled over in connection with another shooting investigation and video of this whole thing was rolled on and posted by witness on facebook. play part of it for you, abut just a warning, it is disturbing to watch. >> our cnn national correspondent is following this story for us and, brynn, tell me