Why did the narrator get caught by the police in "The Black Cat"?

The fact that the
narrator gets caught is an example of his distorted view of reality.  From the opening line the
narrator tells the reader that he has a "wild" story to tell, but that it is
completely true.  He proceeds to tell the story of a cat who haunts him even after the cat is
killed, so in his mind it's a ghost story.  However, the story is somewhat ambiguous because the
narrator admits that he began drinking heavily, and so one might reach the conclusion that the
alcohol has affected his view of reality.  Towards the end of the story the narrator is walking
down the steps of the basement and the cat runs between his legs.  This angers the narrator, and
he picks up an axe to kill the cat (for the second time!) but is stopped by his wife.  In his
anger, he kills his wife with the axe and buries her in the wall.  The cat disappears after the
narrator nearly killed him, and he believes the cat was too scared to come back.  The police
come to investigate the wife's disappearance, and the narrator is so pleased with how well he
hid his wife that he even takes the police to the basement.  In an arrogant gesture, the
narrator bangs on the wall to show the police how strong and well-built the house is.  Once he
does this, he hears a loud wail from within the wall.  As it turned out, the narrator
accidentally buried the cat inside the wall when he was sealing his wife in the wall.  In the
end, his distorted view of reality and his overconfidence is the reason why he is caught.