BOSTON (AP) — A friend of Boston Marathon bombing suspect Dzhokhar Tsarnaev is believed to have provided the handgun used to kill a Massachusetts Institute of Technology police officer during the manhunt, people with knowledge of the investigation said Tuesday. The 9 mm Ruger pistol described in the indictment is the same handgun that was used to kill MIT police officer Sean Collier during the manhunt for the bombing suspects, according to the two people who spoke on condition of anonymity because they were not authorized to discuss the investigation. According to the indictment, Silva knowingly had possession of the gun, "which had the importer's and manufacturer's serial number removed, obliterated, and altered and had previously been shipped and transported in interstate and foreign commerce."