The Crossing Places (Ruth Galloway, #1)
Forensic archaeologist Dr. Ruth Galloway is in her late thirties and lives happily alone with her two cats in a bleak, remote area near Norfolk, 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. 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 the site near Ruth's remote home?