City of Widows — Loren D. Estleman

Page Murdock has been sent to the tough New Mexico of 1881 to track down a man and bring him to justice. But more than a trail of revenge, Murdock finds himself on a desperate odyssey. For in the Southwest a friend can turn out to be one's cruelest enemy, an enemy one's finest friend. And the woman Murdock loves will be as voluptuous as Venus and wicked as sin.