On April 15, 2013, two bombs were detonated during the 2013 Boston Marathon around 2:50 p.m. in Copley Square, just before the finish line.
Arredondo was photographed helping various victims of the bombings, including running alongside a man who had his legs blown off in the blast so he could help put pressure on the man's exposed arteries to keep him from bleeding out.
He is being lauded as a hero by the press and the general public for his acts of selflessness and bravery. Arredondo was a spectator of the race, there to support a runner who was doing the race in memory of Arredondo's son, a fallen Marine