The deep dark descending - Allen Eskens

A homicide detective hunts down his wife's killers while struggling between his thirst for revenge and a twinge of conscience forbidding him to take the law into his own hands.

Homicide Detective Max Rupert never fully accepted his wife's death, even when he believed that a reckless hit-and-run driver was to blame. Haunted by memories both beautiful and painful, he is plagued by feelings of unfinished business. When Max learns that, in fact, Jenni was murdered, he must come to terms with this new information-and determine what to do with it.

Struggling to balance his impulses as a vengeful husband with his obligations as a law enforcement officer, Max devotes himself to relentlessly hunting down those responsible. For most of his life, he has thought of himself as a decent man. But now he's so consumed with anguish and thoughts of retribution that he finds himself on the edge, questioning who he is and what he stands for.

On a frozen lake at the US-Canadian border, he wrestles with decisions that could change his life forever, as his rage threatens to turn him into the kind of person he has spent his entire career bringing to justice.