Below Zero — C.J. Box

It begins with a phone message: Tell Sherry April called. And suddenly Joe Pickett's family is shaken to the core. April, Pickett's foster daughter, was murdered six years ago. His daughter Sherry starts to believe there's a chance that April is still alive. Joe, however, remains suspicious, especially when he discovers that the calls have been placed from locations where serious environmental crimes have occurred. And as the caller moves closer, unsettling questions are raised. Is this young girl April? Are Joe and his family the victims of a cruel hoax? And can they face the harrowing truth?