A Sea of Troubles — Donna Leon

The murder of two clam fishermen off the island of Pellestrina, south of the Lido on the Venetian lagoon, draws Commissario Brunetti into the island's close-knit community, bound together by a code of loyalty and a suspicion of outsiders worthy of the Mafia. When his boss's secretary Signorina Elettra volunteers to visit the island, where she has relatives, Brunetti finds himself torn between his duty to solve the murders, concerns for Elettra's safety, and his not entirely straightforward feelings for her...