FBI appeals for help solving marathon bombings

Law enforcement agencies pleaded 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. Officials circulated information about the bombs, which involved kitchen pressure cookers packed with explosives, nails and other lethal shrapnel. Federal investigators said no one had claimed responsibility for the bombings (which took place on one of the city's biggest civic holidays, Patriots Day). Below, video of the event and the growing global response to it.

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