At the very beginning of the story, the narrator states that he will “healthily and calmly” tell us his story. Still, just before, he mentions that he was and is terribly nervous and that he is affected by a certain disease that enhances the accuracy of his senses. “I heard all things in heaven and in the earth. I heard many things in hell. How, then, am I mad?” (42) Moreover, for a moment, the narrator is unable to remember how the idea came to his mind of getting rid of the old man’s evil eye as if he never had any specific intent when he did the deed. The reader is then convinced that the narrator is mentally unstable and cannot be taken at face value.
One of the elements of doubt regarding the veracity of the murder is when the narrator described what he did with the corpse. He assures us that there was no stain of anything and that he had carefully placed the body between the scantlings underneath the floor. Logically, the old man’s cadaver and his blood would have produced a fetid smell in the old man's room. The smell of putrefaction would surely have been detected by the three policemen when they arrived and were chatting with the suspect on the crime scene. Another piece of evidence is the policemen’s behaviour when the suspect becomes quite agitated and strange because he is hearing a steadily increasing noise. Policemen on a crime scene would not continue to smile and converse when a