April 16, 2013 The investigation into the explosions that killed three and injured dozens continues. We're tracking developments.
April 16, 2013 These days hospitals drill for mass casualty disasters like the explosions at Monday's Boston Marathon. But when it happened for real, the first response was disbelief. Then the victims began arriving. Doctors say they were confronted with the kinds of IED injuries that U.S. troops have gotten in Iraq and Afghanistan.
April 16, 2013 Washington, Los Angeles, New York and San Francisco were among the cities taking action following the blasts.
April 15, 2013 Bill Iffrig, 78, finished second in his division despite being knocked over by an explosion at the Boston Marathon.
April 15, 2013 Even as the shock and horror of the deadly explosions at the Boston Marathon had yet to subside Monday, people were turning to online tools to check on the safety of their friends and family who were at the event. The latest estimates of the casualties include more than 3 dozen people injured, with two dead.
April 15, 2013 President Obama said whoever perpetrated the attack on Boston would feel the full weight of justice.
April 15, 2013 Witnesses say the two explosions were followed by panicked and bloodied spectators as emergency services personnel rushed to the scene.
April 15, 2013 NPR's Dina Temple Raston reports that the FBI has sent counterterrorism officials to the scene. The blasts happened in quick succession four hours after the beginning of the men's race while thousands were still out on the course.