The Ice Sisters by R. Herron, published by Bookouture is book 10 in the Detective Ellie Reeves Series.
There are cross-overs to previous books, but this book can be read as a stand alone.
Ellie is on vacation, a much needed time out from personal drama. On her last day, no her last hour she manages to get in deep trouble. She needs rescuing from Cord McClain and Derrick Fox. The ranger and the special agent don't really see eye to eye. One of them is rather jealous. She gets rescued at the last minute, and discovering the bodies of little twinsisters.
In addition to her complicated privat life, she's hunting for the girls killer.
Highly suspenseful, literally unputdownable, a binge read, 5 stars.

What a gripping book. There was so much confusion in what was really going on. It was fascinating to follow as the task force tried to figure it all out. The children broke my heart. It was so sad at parts. The ending was very interesting.