Report: one of Boston Marathon bombs possibly made from kitchen pressure cooker

LA Times: "Investigators believe at least one of the two bombs in Boston was made with a pressure cooker, according to law enforcement and intelligence officials." MSNBC: Authorities have recovered forensic evidence that leads them to tentatively conclude the bombs "consisted of an explosive and shrapnel — BBs and pieces of nails — packed inside a pressure cooker," then hidden in a backpack. Boston Globe: a circuit board was found near the blasts.