On the third day of the Boston Marathon bombing investigation, authorities have combed through the blast sites on Boylston Street. These new photos released by the Joint Terrorism Task Force of Boston show contents of two bombs constructed from a pressure cooker and projected BBs, ball bearings, and tiny nails during the explosions. FBI specialists are examining blood-covered zipper and nails, a dented Tenergy battery used to power toy cars and trucks, orange and black wires, shredded nylon parts, and a green circuit board used to trigger the bombs. As specialists continue to search for clues, all types of evidence—from the videos and photos of bombing evidence at the marathon's finish line—will be crucial in identifying and tracking down suspects.
Photos: Boston Marathon bombing evidence
On the third day of the Boston Marathon bombing investigation, authorities have combed through the blast sites on Boylston Street.