P. D. James 
Unnatural Causes 

Maurice Seton was a famous mystery writer — but no murder from his imagination could equal the ghastliness of his own death. When his grotesquely mutilated corpse is found in a drifting dinghy, ripples of horror spread among his bizarre neighbours: the cruel and cynical drama critic, the celebrated recluse, the rakish young heir, the terrified woman waiting for her killer in a lonely house… It is up to Superintendent Adam Dalgliesh and his extraordinary aunt to discover the shocking truth about Seton’s past — before the plot takes another murderous turn.From the Paperback edition.