Showdown at Verity — T.A. Mort

Manhunter

He comes from another territory--the American Northeast--and another time: before war, before loss, and before he found a calling as a hunter of men. The deadliest stranger in a land of strangers, he's the worst enemy an outlaw could ever have....

Ethan Black has seen too many good people die to regret killing the bad ones. An educated man, a former sailor who shelled Vicksburg for the Union Navy, Black has come to Hell's own training ground on the Mexican border. The Pinkertons want him to find out who hijacked an army payroll and left eight soldiers dead beneath the blazing sun. In an unforgiving land where Apache, Mexicans and white settlers live in a dangerous state of lawlessness, everyone points the stranger to their favorite suspects. But Black never takes anyone at their word. And amid ambush and bloody betrayal, he's right at home: flushing out a murderer who must find a way to take out the stranger quick--or pay with his life...