Evidence recovered from the scene of the deadly blast in Boston Monday is being investigated by authorities.<br/> <br />Photos show the remains of an explosive device that include twisted metal containers, wires and a battery in what appears to be a small circuit board.<br/> <br />Officials say the evidence is being reconstructed at an FBI lab in Virginia.<br/> <br />FBI SPECIAL AGENT RICHARD "RICK" DESLAURIERS, SAYING:<br/> <br />"Among items partially recovered are pieces of black nylon which could be from a backpack and what appear to be fragments of BBs and nails possibly contained in a pressure cooker."<br/> <br />Authorities say the investigation is still in its infancy and that there are no claims of responsibility.<br/> <br />Three people were killed in the twin blasts, 176 others were injured.
