Shawdows at Dusk by Elizabeth Goddard

Book 2 of Missing Alaska

Summary: 

Montana Detective Trevor West is desperate to learn what happened to his sister, who went missing in Alaska over a year ago, leaving nothing but a few photographs as clues to her whereabouts. At the advice of Police Chief Autumn Long, Trevor enlists the help of an experienced bush pilot. If Carrie James can't help him find the places in the photographs, no one can.

But Carrie has her own agenda. Grieving the death of her closest friend and the only person she could trust, Carrie will help Trevor find his sister on one condition--that he help her track down her friend's killer.

As the two close in on the answers they crave, they'll face dangers and connections they could not have imagined. They'll have to learn to trust one another--and face the dark secrets of the past--if they are ever to discover the truth and bring a killer to justice.

Opening Lines:

The old cargo plane vibrated as the pilot descended into the airdrop zone, the turbulence shuddering through Carrie James. She braced herself on a bench a few feet from the secured freight--emergency supplies that could mean the difference between life and death in a food-starved, war-torn country.