Emilia Cruz, the gritty but stylish police detective at the center of the author Carmen Amato’s mystery series, has a foot planted in both of the worlds that dominate the world-famous resort city she serves — Acapulco.

She moves easily, but not without guilt, between the glitzy beachfront hotels that dominate Acapulco’s skyline and the hyper-violent crime and corruption that seethes beyond that luxurious tourist bubble.

As a lover, she lives in the bubble with her boyfriend, the manager of one of those gleaming hotels. As a cop, she tackles the worst that other world of crime and corruption serves up, battling ruthless narcos and crooked politicians and officials, including more than a few who also wear a badge and hate her for being honest and a woman.

Fans of Amato’s earlier work are familiar with this dynamic and the emotional strain and guilt Cruz feels and the author so deftly portrays. In her latest Cruz novel, Russian Mojito, Amato uses this to heighten the tension of the double mysteries presented within — the kidnapping of the detective’s stepfather by a gang known as Los Colectores and the murder of a Russian travel writer in the hotel where she lives.

The kidnapping touches on another ongoing storyline of the Cruz novels — her tortured relationship with her mother, a trauma-scarred woman who retreats into simple-minded focus on a rosy version of the past to avoid the reality of the present. The mother also wants to avoid a painful memory — giving away her son, Cruz’s brother, to a wealthy woman when their father is killed in a car wreck. The brother becomes a criminal monster known as El Acólito, who becomes a taunting obsession Cruz can’t catch.

The primary action in Russian Mojito centers on the kidnapping and the murder case, stretching Cruz, whose nerves are already shattered from her last case, as thin as a guitar string that’s about to snap. The kidnappers’ ransom demand is unusually high and they don’t seem willing to negotiate. And the murder case leads Cruz and her hard-charging former partner and current boss, Franco Silvio, to the trail of gasoline thieves, known as huachicoleros, and the double-murder of a wealthy Russian hotelier and his wife who had made Acapulco their home.

As always, Amato spins a taut tale, keeping the reader off balance and guessing just as much as Cruz does. The pace is swift and the action is realistically and unflinchingly portrayed. Cruz is a tough but tortured cookie, driven by guilt and obsession. And that’s what makes her so damn interesting.

The author provided a copy of this book in exchange for an honest review.