Max Brand 
On the Trail of Four [EPUB ebook] 

When Hugo Ames found Truck Janvers dying from gun wounds in his mountain shack all the old miner had time to say was, “My boy—San Marin—” before a knife, hurtled out of the darkness, silenced him forever. By morning Ames had found the tracks of the four men who’d brought Truck down to die without giving him a fighting chance.

Even though Ames was an outlaw with a price on his head, he’d never harmed a defenseless man, and he couldn’t stomach men who did. So he left the safety of the hills to track down the cold-blooded killers—and rode straight into the greatest danger of his life!