All Must Die - Cassidy Yates, #12

A spree of unexplained murders shocked Monotony's townsfolk, but when bank raider Sykes Caine was caught the killings stopped. Although Sykes pleaded his innocence, he got ten years. When Sykes is freed from jail, he returns to Monotony where Sheriff Cassidy Yates has to deal with another perplexing case. Two men are killed in what appeared to be an act of revenge, but Cassidy notices similarities with the deaths ten years ago.
Before long, other people are gunned down and the evidence points to Sykes again being responsible. With time running out before someone takes the law into their own hands and Sykes receives summary justice, Cassidy must uncover the truth and ensure only the guilty are punished.