Joseph Mascouvin reports to the police that he has found a note on a blotter in a café saying that a fortuneteller will be murdered at 5:00, and in fact, Miss Jeanne is found murdered shortly after. Locked in her kitchen is an old man, Picard, actually her father, who has been masquerading for ten years as Octave Le Cloaguen, so that Mrs. Antoinette Le Cloaguen can continue to receive the yearly income payable to her husband as long as he lives. Picard had been a tramp in Cannes at the time of Le Cloaguen's death, and Mrs. Le Cloaguen had spotted him as closely resembling her husband. Jeanne's body was found by Mrs. Roy, who kept an inn, the Pretty Pigeon, where Maigret stayed and met Émile Blaise, in fact a most cunning and pitiless blackmailer, using the gangster Justin of Toulons to collect money and get tough with those who didn't pay, and Mascouvin and others to supply him with information others would pay to have kept quiet. Mascouvin read his firm's letters, and copied out anything of value. Miss Jeanne had access to people's secrets, and was another informer. Justin had spotted Picard at Jeanne's, followed him home, and set up the blackmail of Mrs. Le Cloaguen. Jeanne (Marie Picard) had no doubt found out, worried for her father, and perhaps threatened to give the game away. It was decided to ask Mrs. Le Cloaguen for an entire year's annuity, and for Justin to kill Miss Jeanne at 5:00. Mascouvin had known, perhaps been told to frighten him, but feeling guilty, had stumbled on a way to notify the police.
This report prepared by Dana Samson