A lost video now reveals the terrifying moments on the Boston Marathon course, when runners were just learning what had happened at the finish line.
The runner who captured the video never thought she would see it again. She began recording at the start line, but in the chaos, she lost the camera.
Thanks to a stranger who found the camera, and went out of his way to find her, she is reliving the panic three weeks later.
Katie Eastman is a reporter for the Boston Herald. She was capturing the joy of the marathon for the paper using a small, point of view camera called a GoPro.
At mile 25, she realized, she would be telling a very different story.
In the video, Eastman hears someone say two bombs went off at the finish line. When she asks a police officer, he tells her to keep running.
The confusion turns to panic, the exhaustion to adrenaline, as Eastman runs toward the finish line hoping to find out what happened.
"My sister and my mom are there," Eastman tells another runner in the video. "Let's just get there."
Eventually, she was forced to stop as a police officer announces the marathon is canceled. For Eastman, it is tough to watch.
"It just immediately brought me back there, to the panic," she said.
But Eastman thought she would never see the video again. She lost it in the aftermath, only to have it returned by a couple from California. They found it, found Eastman and mailed it back to her almost three weeks later.
Eastman used the video to finally do the story she set out to tell, but with a new element, her and her sister running the last mile and a half she never got to finish.
"I had to go back and finish the race. That's the end of the story. The spirit of Boston is the end of the story."