Article Photos: FBI issues photos of 2 suspects in Boston bombing 2/43

Officials stand guard near the site of the Boston Marathon explosions, 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)