The world-famous locked-room mystery from a master of detective fiction A frightful act of malice committed in Paris: the dastardly attempted assassination of the daughter of a famed scientist who was working late in his laboratory with an assistant when the attack took place in the adjacent room. A locked chamber, windows barred, no one hiding inside. The poor young lady unconscious, covered with blood, violent marks on her throat and a wound at her temple. The scientist's revolver removed from its cabinet and sealed in the room with her. The only trace of her assailant is a large, bloody handprint on the wall. At a loss, the chief of the S