The Spiral Path — Richard Grindal

Everyone had agreed that the industrialist Mark Bascombe had committed suicide, even the coroner. Only Bascombe's son David believed - or professed to believe - that it was murder. And it was he who had hired private investigator John Bryant, rather belatedly it is true, to investigate his father's death.

Bryant soon realises that everyone has a secret: Bascombe's wife; his daughters; Colonel Legge; Oscar and Moira Patton: they were all bound together in a series of conflicting and hidden relationships. And the central character - the man who had every answer - was already dead.