The Crossing Places. The First Ruth Galloway Mystery

The first entry in the acclaimed Ruth Galloway British crime series follows the "captivating"* archaeologist as she investigates a child's bones found on a nearby beach, thought to be part of a decade-old cold case. Forensic archeologist Dr. Ruth Galloway is in her late thirties. She lives happily alone with her two cats in a bleak, remote area near the Norfolk coast, land that was sacred to its Iron Age inhabitants-not quite earth, not quite sea.
But her routine days of digging up bones and other ancient objects are harshly upended when a child's bones are found on a desolate beach. In this gripping police procedural, Detective Chief Inspector Nelson calls Galloway for help, believing they are the remains of Lucy Downey, a little girl who went missing a decade ago and whose abductor continues to taunt him with bizarre letters containing references to ritual sacrifice, Shakespeare, and the Bible.
Then a second girl goes missing and Nelson receives a new letter-exactly like the ones about Lucy. Is it the same killer? Or a copycat murderer, linked in some way to Ruth's remote home?*Louise Penny