Title: The Prone Shooter's Position - Jean-Patrick Manchette - book
Summary :
Martin Terrier was poor, lonely, stupid, and mean, but to change all that, he had a life plan as beautiful as a straight line. After practicing the profession of assassin for ten years, making his mark, and learning good manners, he was going to return home to find his fiancée and make waves... But to bathe twice in the same river, a lot of blood must flow under the bridge.