Nothing to Lose by JA Jance

 Back in the day, when JP "Beau" Beaumont was a Seattle cop, his partner was Sue Danielson. She was a single mom of two boys, with an ex with a nasty temper. On a night that has haunted Beau for years, the angry ex shot Sue then killed himself. Beau managed to get her two young sons out of the house before they were the next victims but he couldn't save Sue. The boys were sent off to Ohio to live with their grandparents and that was the last Beau heard of them until the oldest, Jared, now a priest, showed up on Beau's doorstep hoping to hire him (Beau is now a PI) to find out what happened to his younger brother, Chris, who had run away to Alaska to be with his other grandparents years earlier. 

So Beau heads to Alaska to find out what happened to Sue's youngest son. And with a little help from some friends he meets along the way, he manages to piece together the mystery of what happened to Chris. It's a good story made even better by a colorful Alaskan named Twink, who chain smokes her way through Alaska while serving as Beau's driver.