Strip away umpteen red herrings and plot hinges on supposed "perfect murder plot" of person opening door of a safe, triggering a pistol shot that presumably would later be considered a suicide. However, even though story takes places in 1940s, crime detection had evolved to pint that authorities would look askance at supposedly self-inflicted gunshot wound in which victim had no gun powder on hands consistent with a death of this nature, nor that average suicide could ever shoot oneself directly straight ahead as occurred in this scenario, etc.