Here is the complaint in Bishop Paiute Tribe v. Inyo County (E.D. Cal.):
An excerpt:
This action is for declaratory and injunctive relief by the Bishop Paiute Tribe (“Tribe”), a federally recognized Indian Tribe, against Inyo County, the Inyo County’s Sheriff and District Attorney, for the arrest and prosecution of a Bishop tribal law enforcement officer for performing his duties on the Tribe’s Reservation. The Tribe seeks an order declaring that Defendants are interfering with the Tribe’s inherent sovereign authority to take action, defined by federal law, against non-Indians perpetrators on tribal lands. Federal law establishes that tribes have inherent authority over non-Indians on tribal lands to stop, restrain, detain, investigate violations of tribal, state and federal laws, and deliver or transport the non-Indian to the proper authorities. Duro v. Reina, 495 U.S. 676 (1990), Ortiz-Barraza v. United States, 512 F. 2d 1176 (9 th Cir. 1975). Defendants have arrested, and criminally charged, Daniel Johnson, a duly authorized Bishop tribal law enforcement officer, while he was executing federal prescribed police duties against a non-Indian, on the Tribe’s Federal Reservation.
News coverage here.
Turtle Talk 
The Tribe acts to protect local citizens. It is pure dumb for the County to harass the tribal police.
Thanks for civil rights law that allows the Tribe to sue over the matter. Recall a similar case arose in CA when tribal police were arrested for driving a car, with red lights, off the Reservation. They became commissioned federal officers and won the case. Just when you think things are going good, some idiots like the story above, come along and display their ignorance and racism.