JM 9-60.1010
The offense of motor vehicle theft was traditionally an offense that was prosecuted by State and local law enforcement agencies. In view of the increase of motor vehicle theft and the use of violence in connection with that offense, the Attorney General was directed by the Congress to have the Federal Bureau of Investigation (FBI) and the United States Attorneys' Offices cooperate with State and local officials to investigate carjacking, and, when appropriate and consistent with prosecutorial discretion and resources, prosecute violators in Federal court.