The devil stone - Caro Ramsay

In the village of Cronchie, a wealthy family are found brutally murdered. The Devil Stone, an heirloom rumoured to bring death if removed from their home, is the only thing stolen. The key suspects are known satanists. But when the investigating officer disappears, DCI Christine Caplan is pulled in to investigate.

Caplan knows she is being punished for a minor misdemeanour when she is seconded to the Highlands, but she's confident she can quickly solve the murders and return home to her fractious family. But as she closes in on the truth, it is suddenly her life, not her career, that is in danger.