Two powerful explosions rocked the finish line area of the Boston Marathon on Monday afternoon. Police, racing to determine whether it was a terror attack, said two people were killed and scores injured. Phil Kirkpatrick, a 59-year-old from Nashville with blood on his jeans and shoes, was watching his girlfriend race. "There was a large explosion and a white flash," he said. "It blew us all back onto each other. It was so loud, I still can't hear out of my right ear. I was crawling on the sidewalk, and my cell phone blew out of my hand." Another man, a block away from the blast, called it "100 times louder than thunder." Athletes walking away from the race course began running again.
In this image from video provided by WBZ TV, spectators and marathon runners run from twin explosions at the finish line of the marathon on April 15, 2013.