Crooked River by Valerie Geary

Two young girls are visiting their father outside of Bend, Oregon.  One summer day they discover the body of a young women in the river outside the rural property where they share a teepee with their dad.  This has been a summer adventure for older sister Sam for a few years but with the death of their mother, her younger sister Ollie has joined her.  Ollie has not spoken since her mother's death out of fear that her voice will be replaced by the voices of the spirits she sees all around her. When their father is accused of the murder of the women, Sam begins a search for the real killer.  An intriguing mystery with an interesting local connection.