"The Bone Orchard" (Minotaur Books), by Paul Doiron

Mike Bowditch's recklessness and insubordination, along with his struggle with a series of personal tragedies, seemed to make him a bad match for his job as a Maine game warden. So, as the fifth novel in this fine series opens, it comes as no great surprise that Mike has quit law enforcement and taken refuge as a fishing guide in the state's great North Woods.

But Sgt. Kathy Frost, Mike's former mentor in the warden service, is in trouble. A suicidal Afghanistan war vet she was assigned to help has been shot dead. The ex-soldier's politically connected parents and former army buddies blame her. And she is under investigation for her role in the affair.

Thinking he might be able to help, or at least offer a sympathetic ear, Mike drives to her cabin and comes under sniper fire in her driveway. He finds his old friend critically wounded.

A civilian now, Mike has no business getting involved. As reckless and impetuous as always, he dives in anyway.

The authorities suspect the dead soldier's old army buddies for the attack on Kathy. Mike casts his net wider as he pursues the case from the urban landscape of Portland to the desolate farming villages of Aroostook County. As always, Doiron describes his state so vividly that it becomes not just the setting but also a character in its own right.

As Mike's list of suspects grows, he digs deeply into Kathy's past. Along the way, he also keeps running into people from his own past, including old friends, old enemies and an ex-wife.

The encounters lead to much soul-searching — so much that for a good portion of the book, the biggest mystery Mike confronts isn't who shot Kathy, it's what kind of man Mike has become. This makes "The Bone Orchard" both a rich exploration of character and a satisfying mystery story.