CNN CNN Newsroom April 18, 2014 19:57:00
12,000 videos from businesses and marathon spectators, something unmistakable at the second blast site. >> you see a man in a white ball cap, the hat is turned around backwards, walking into the frame of the shot. >> he places that backpack down on the ground, sliding it off his shoulder. a short time later, 15 minutes later, he makes a cell phone call and after that cell phone call concludes, very shortly there after you hear the first bomb go off farther off near the finish line. he glances quickly to his left but walks diligently and deliberately to the right. about 15 seconds after he depa...