Carlos Arredondo ran across Boylston Street, jumped the security fence, and landed on a sidewalk smeared in blood. In front of him, two women lay motionless. Another woman walked around in black-powder smoke, looking down at the fallen bodies.
"Oh, my God," he said she repeated, dazed. "Oh, my God."
Arredondo had been a Boston Marathon spectator, carrying a camera and a small American flag. He dropped the flag. He took four pictures — focusing on a young man crumpled on the sidewalk. The man had a blank expression, and a leg that was only bone below the knee.