The Wrong Bones (Widow's Island #10)
Melinda Leigh

Deputy Tessa Black spots a man disturbing a grave in the local cemetery and gives chase. But when Tessa catches him, she learns that the ghoulish trespasser wasn’t robbing graves; he was burying a box of bones.
With the help of her fiancé, park ranger Logan Wilde, Tessa discovers that the remains belong to a missing teenager from a nearby island. After the girl disappeared nine months ago, police labeled her a runaway. Now, though, it’s clear the teenager was murdered.
When the only witness is an uncooperative teenager, Tessa and Logan must find the killer before the boy becomes the next target.