In 1973 Banks went to Pine Ridge Indian Reservation in South Dakota when the local Lakota civil rights organization asked for help in dealing with law enforcement authorities in nearby border towns. Residents of Pine Ridge believed the police had failed to prosecute the murder of a young Lakota man. Under Banks' leadership, AIM led a protest in Custer, South Dakota in 1973 against judicial proceedings that had resulted in the reduction of charges of a white man to a second degree offense for murdering a Native American.