In "The Tell-Tale Heart," Poe uses irony to help develop suspense. Much of this irony is dramatic irony--situations in which characters are unaware of information to which the reader is privy. Here are three examples of dramatic irony in the story. First, the old man is totally unaware that the narrator harbors such ill feelings towards his "vulture" eye. The narrator describes a "cold feeling" that runs through him every time the old man looks at him with the eye, so he resolves to kill him, unbeknownst to the old man. Second, during the plotting of the murder, the narrator sneaks into the old man's room for eight nights to wait for the perfect moment to execute his plan. But in the morning, the narrator acts warmly to the old man. The old man still has no idea what will soon be his fate. Finally, at the end of the story, the police officers are unaware that the old man has been buried under the floorboards, so they search the house and sit to have a drink with the narrator. The reader is fully aware of the details of the story, while dramatic irony keeps important details hidden from certain characters in the service of developing suspense.