The Devil in Disguise by Martin Edwards
Harry Devlin is hired by his clients, the Kavanaugh Trust, to contest the will of their late patron. Instead of leaving his substantial wealth to the Trust as promised, Charles Kavanaugh has left everything to his newly-appointed housekeeper, the sinister Vera Blackhurst. Devlin employs a private investigator to discover the secrets of Blackhurst's murky past. Then the current chairman of the Kavanaugh Trust is found dead, fallen from the third floor window of a local hotel. Did he jump - or was he pushed