Fatal Error (1970)

At the end of the 19th century, the Wyoming Oil Company has established itself in the vicinity of Wind River City at the foot of the Rocky Mountains, where they have been illegally pumping oil from Native American territory. One of the company's greedy agents, Mike Allison, kicks out both his white partners and the Native Americans. He has his some of his associates secretly murdered and blames it on the Native Americans, who are then killed when they get in the way of his plans. Five chiefs with lifelong shares in the Oil Company die mysteriously as a result. The young chief Shave Head asks his a half-blooded brother Chris Howard for help.

Unfortunately the movie Fatal Error is not yet available on HBO Max.