“The Bitterroots: A novel” (Minotaur Books), by C.J. Box

After losing her job as a North Dakota sheriff following a tumultuous serial killer investigation in “Paradise Valley,” Cassie Dewell resurfaces as a struggling Montana private detective in C.J. Box’s new crime novel, “The Bitterroots.”

As a former law enforcement officer, she’s doesn’t want to work for defense attorneys, but when a local lawyer asks her for help, Dewell, the single mother of a teenage boy, can’t afford to turn down the case. Dewell is repulsed that the lawyer’s client, Blake Kleinsasser, is accused of raping his 15-year-old niece, but the lawyer assures her that the case against him, including witness statements and DNA evidence, appears solid. Assure me that there are no holes in the case, the lawyer says, and I’ll talk my client into a plea deal.

Kleinsasser, who had recently returned to Montana after working as a New York City stockbroker, is the oldest son of a clan that owns the vast Iron Cross Ranch and just about everything else in their mountain-ringed town. It turns out that his father and brothers despise him for turning his back on the family’s ranching heritage.

If the rape case against him is as solid as it appears, Dewell wonders, why are the sheriff and Blake’s family members going to so much trouble to stop her from doing her job?

By the time Blake is beaten so severely in prison that he lapses into a coma, Dewell discovers that the rot in the Kleinsasser family runs deeper than she could have imagined.

Box’s characters are well developed, his writing is vivid, the tension runs high, and the plot unfolds at a rapid pace.