The Singing of the Dead by Dana Stabenow

A dual time line this time, a bit of a departure for Stabenow. The life and death of a woman a hundred years ago precipitates murder in the here and now of the story. The primary setting is political; a candidate for the state senate is receiving threatening letters and Kate is hired (against the wishes of the campaign manager) to protect her.

The situation with Johnny Morgan provides a second thread. Remember, when Kate returned to her cabin after reluctantly crawling out of the hole she tried to hide in after Jack's death, she found Johnny there waiting for her. What we weren't aware of at the time was that his mother, in an effort to remove him from Kate's influence, had taken him to Arizona and dumped him on her mother in her retirement community. He had run away and hitchhiked back to Alaska - at age 14. Of course, he had been running away from his mother for years.

Since Jack's last words to Kate were a request that she look out for Johnny, she does her best to do it. Jane does finally figure out where he must be and comes for him and, eventually, most of the Park is in on the game.

As for the Kate/Chopper Jim thing, Stabenow is still trying hard to recreate the character. I don't believe he is referred to as "Chopper Jim" in this book at all. They are still at the mutual antagonism stage - and Kate has the opportunity to renew an old, old flame, much to Jim's displeasure. Still, he does come valiantly to her rescue when she falls afoul of the murderer.