Maigret's Failure

Description for MAIGRET'S FAILURE by Georges Simenon:

Was Maigret himself guilty? The question haunted the great French detective as for the first time he had to examine not only a baffling list of suspects but his own conscience in seeking the killer of a man everyone hated, including Maigret himself. Maigret knew all too well that he easily could have prevented the death -- and that even now he might be letting a murderer already within his grasp escape the consequences of a crime that Maigret could not find it in his heart to condemn...

This is #49 in An Inspector Margret Mystery.