Like the miners in his fictional Iron Range county of Tamarack, William Kent Krueger, in his new mystery, "Vermilion Drift," digs ever deeper and wider into the richly veined life of private investigator Cork O'Connor. In this 10th installment, the former sheriff is at a crossroads. His wife, Jo, is dead and their two daughters are beginning to make lives of their own, out in the big world. Their teenage son is also away for the summer, working on a friend's ranch. Cork knows he must forge a new life for himself, but he's not sure how.

And so he throws himself into his work, accepting a job from the owner of the nearby mines. Really, it's two jobs. One is to find out who's been sending threatening notes to mine officials. The other is to find the owner's flamboyant sister.

The notes are no doubt coming from someone upset by the prospect of the Atomic Energy Commission using an old mine for storage of nuclear waste. But the discovery of Lauren Cavanaugh's body in a boarded-up mine shaft raises more questions than it answers. Hers is just the most recent of six women's bodies sequestered there. The others, Cork soon realizes, date to "The Vanishings," a time 40 years earlier when a series of women from the bordering Ojibwe reservation disappeared.

As Cork delves into the case, he must also confront, with the help of his mentor and friend Henry Meloux, his own repressed memories and troubled relationship with his father. Although the two had a close relationship, it had been strained by the then 13-year-old Cork's frustration with his sheriff father's inability to solve the disappearances. Forty years later, the discovery of the bodies makes Cork question his memory of his father's integrity.

During a rigorous sweat lodge healing, the aging Meloux guides Cork to a level of understanding and acceptance that places compassion above the letter of the law and that "feeds" love rather than fear.

Krueger lays all this out with remarkable sensitivity and emotional depth, one reason why this series of mysteries is so satisfying. He also is a master at pacing. Once you begin a Cork O'Connor mystery, it's hard to put it down. They do not need to be read in sequence, but each builds on the one before, creating a world and characters so real that you'd swear you could drive up and visit them sometime.

While Krueger frequently takes on topical issues, "Vermilion Drift" is his best yet, dealing with how we as a community and individuals dispose of unwanted things, whether it be nuclear waste or difficult memories.

Kathe Connair is a copy editor at the Star Tribune.