Broken Bay by Margaret Hickey

Detective Sergeant Mark Ariti is in Broken Bay on a fishing trip when Mya Rennik goes missing while diving in a sinkhole. As authorities are bringing her body to the surface, they discover that the remains are not those of Mya, but of Eloise Sinclair, who went missing twenty years ago. Mark is asked to stay in town and start on the investigation concerning Eloise until the special investigations team arrives. The Sinclairs are well known in the town-- Eloise's mother Juliette committed suicide when Eloise was a baby. Could Eloise's death be connected to Juliette's suicide?  Mark also delves into the personal relationships between Eloise, her best friend Gerri, and the others in their group: Gerri's twin brother James, and Eloise's brothers (Mat, Nic, and Phil) who all still live in Broken Bay. Will Mark be able to bring Eloise's killer to justice? Broken Bay is the third book in the Mark Ariti series.