Investigators look through the top of a building on Boylston Street, two days after two bombs exploded just before the Boston Marathon finish line, Wednesday, April 17, 2013, in Boston. Authorities investigating the deadly bombings have recovered a piece of circuit board that they believe was part of one of the explosive devices, and also found the lid of a pressure cooker that apparently was catapulted onto the roof of a nearby building, an official said Wednesday.(AP Photo/Julio Cortez)
Gallery: Bombing investigations and memorials
Apr. 17, 2013 @ 02:17 PM
BOSTON -- Investigators combed through the scene of Monday's explosions in Boston the victims were remembered with memorials and vigils.