Reporters and camera crews flocked to the scene on a report an arrest had been made in connection with Monday's marathon bombing
PHOTOS: Explosions Rock Boston Marathon
(Boston, MA) -- A bomb threat is forcing a federal courthouse in Boston to close for the day. It comes after speculation swirled about a possible arrest in the Boston Marathon bombing. Attorneys, staffers and members of the media were told to leave the scene. No device was found. Boston Police and the FBI both refuted reports of the arrest.