"Detective Clayton Istee investigates New Mexico borderland killings by an elusive Mexican assassin with ties to a drug cartel. In Michael McGarrity's final, propulsive Kevin Kerney novel, the nightmare of the Mexican drug wars spills across the border with the discovery of a couple in a Las Cruces hotel, scalped with their throats cut. Because of the unusual MO, Detective Clayton Istee suspects that the murders are drug related, but a lack of evidence...