25 U.S.C. § 2815: State, tribal, and local law enforcement cooperation

The Attorney General may provide technical and other assistance to State, tribal, and local governments that enter into cooperative agreements, including agreements relating to mutual aid, hot pursuit of suspects, and cross-deputization for the purposes of—(1) improving law enforcement effectiveness; (2) reducing crime in Indian country and nearby communities; and (3) developing successful cooperative relationships that effectively combat crime in Indian country and nearby communities.