The FBI’s investigation into the bombings at the Boston Marathon was in full swing yesterday, with authorities serving a warrant on a suburban Boston home and appealing for any private video, audio and still images of the blasts that killed three people and wounded more than 140.

Officials said no one had claimed responsibility for the bombings on one of the city’s most famous civic holidays, Patriots’ Day, but the blasts that left the streets spattered with blood and glass raised fears of a terrorist attack.