On Deadly Tides — Melanie Jackson

A body has washed up on the beach and the past which was buried once is now a present danger to Tess MacKay and others in the islands. Questions about the corpse's identity lead to an exhumation of an empty grave and further queries about a supposed accidental death that might be a ritual murder. Unwilling to believe claims of a family bane that kills Wendovers every third generation, Tess sets out to find her missing great-grandfather-- dead or alive.