Maigret's Dead Man // Maigret's Special Murder — Georges Simenon

After receiving a series of mysterious calls from a man who later turns up dead, Inspector Maigret must plunge into the murky Parisian underworld to solve the case

A man calls Maigret from a cafe and asks for police protection, saying he's being followed by men trying to kill him. The next day, the man's body is identified in the street. To catch the killer, Maigret must piece together the details of his dead man's life, leading police into the crowded, fetid underground world of the Paris slums in the process.