BOSTON — Authorities investigating the deadly bombings at the Boston Marathon 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.
A law enforcement official briefed on the investigation confirmed to The Associated Press that authorities have recovered what they believe are some of the pieces of the explosive devices. The official spoke on condition of anonymity because this person was not authorized to publicly discuss evidence in the ongoing investigation.
A person close to the investigation previously told AP the bombs consisted of explosives put in 1.6-gallon pressure cookers, one with shards of metal and ball bearings, the other with nails.
Also Wednesday, a doctor at Boston Medical Center said two patients, including a 5-year-old child, remain in critical condition there. Dozens of others have been released from hospitals around Boston.
Law enforcement agencies pleaded Tuesday for the public to come forward with photos, videos or any information that might help them solve the twin bombings that killed three people and wounded more than 170 a day earlier. Investigators circulated information about the bombs, which involved kitchen pressure cookers packed with explosives, nails and other lethal shrapnel — but the FBI said nobody had claimed responsibility.
"Someone knows who did this," Richard DesLauriers, FBI agent in charge in Boston, said at a news conference where he detailed the type of clues a bomber might have left. "Importantly, the person who did this is someone's friend, neighbor, co-worker or relative."
President Barack Obama branded the attack an act of terrorism but said officials don't know "whether it was planned and executed by a terrorist organization, foreign or domestic, or was the act of a malevolent individual." Obama plans to attend an interfaith service Thursday in the victims' honor in Boston.