Death on Gokumon Island by Seishi Yokomizo

The rockbound and forbidding Gokumon Island was once a pirate stronghold. Now it is home to a clannish fishing community, dominated by two feuding families. When Kosuke Kindaichi arrives bringing news of a death, it triggers a series of grotesquely staged murders. The scruffy detective attempts to untangle the island’s secrets and stop the killings, but a fresh mystery seems to greet him at every turn, and soon he falls under suspicion himself… The fiendish Death on Gokumon Island is one the best-loved classic murder mysteries by the master of Japanese crime.