Is Poe's narrator an example of a reliable or an unreliable narrator Give evidence from the story to prove your point?

Poe's narrator in "The Tell-Tale Heart" is an unreliable narrator. He claims to be completely sane but his erratic behavior and obsession with the old man's eye suggest otherwise. His irrational decision to murder the old man because of his eye color and his eventual confession due to imaginary noises demonstrate his lack of credibility.