The Sundance Murders (Peter McCurtin's Crime Chronicles Book 3‪)‬

The time: 1970. The place: Arizona
Somewhere on the Navaho Reservation a war was set to break out. A war that would plunge the Southwest—eventually the whole country—into bloody chaos. Modern-day Ghost Dance Raiders dressed in the ancient costumes of the peyote cult, and armed with automatic weapons, staged swift, murderous, commando raids against isolated towns.
Berger was caught in the middle, on one side a sinister Indian radical leader, on the other a powerful neo-Fascist rancher with his own private army. Two beautiful girls threw themselves at Berger—and he wondered why. Berger was no ordinary reporter—he carried a gun—and he learned quickly that it wasn’t nearly enough.