Elmore Leonard 
Bounty Hunters [EPUB ebook] 

The old Apache renegade Soldado Viejo is hiding out in Mexico, and the Arizona Department Adjutant has selected two men to hunt him down. One — Dave Flynn — knows war, the land, and the nature of his prey. The other is a kid lieutenant named Bowers. But there’s a different kind of war happening in Soyopa. And if Flynn and his young associate choose the wrong allies — and the wrong enemy — they won’t be getting out alive.