Boston Marathon: Photos from the aftermath of downtown explosions

Medical workers aid injured people at the finish line of the 2013 Boston Marathon on Apr. 15 following two explosions. Authorities carry off the injured, while the stragglers were rerouted away from the smoking site of the blasts. (Charles Krupa/AP)

An aerial view of the scene near the finish line AP/WCVB-TV/ABC)

The scene, after the explosion. (Kenshin Okubo/AP/The Daily Free Press)

Medical workers aid injured people at the finish line. (Charles Krupa/AP)

A Boston police officer wheels an injured boy down Boylston Street as medical workers carry an injured runner. (Charles Krupa/AP)

A woman is comforted by a man near a triage tent set up after the explosions detonated. (Jessica Rinaldi/Reuters)

Public safety officials evacuate the scene. One or more bombs were responsible for the explosions that struck the Boston Marathon as runners crossed the finish line, two high-level law enforcement sources told Reuters. (Neal Hamberg/Reuters)

People react after the two explosions detonated. (John Tlumacki/AP Photo/The Boston Globe)

A Massachusetts state police officer guards the area containing the medical tent following the explosions. (Josh Reynolds/AP)

An unidentified Boston Marathon runner is reunited with loved ones near Copley Square. (Winslow Townson/AP)

This photo provided by Bruce Mendelsohn shows the scene after the two explosions. (Bruce Mendelsohn/AP)