Track Down the Devil by Greg Mitchell

Outlaws are plaguing the Santa Rosa area and Marshal Tim Cleary is sent there to investigate the theft of military rifles. He joins forces with Sheriff Lou Braga in an attempt to break up the gang and to determine the fate of Red Baxter, the freight company driver moving the rifles.Diaz, a delusional Mexican goat herder, claims to have seen the bandit leader and believes him to be the Devil.Now the two lawmen must try to decipher Diaz's terrified ravings and weave their way through false trails and desperate situations before they finally track unmask the Devil and bring retribution.