I believe that the resolution of "The Tell-Tale Heart" begins with the entrance of the police. After the narrator finishes hiding the old man's corpse beneath the floor, a knock is heard on the door. It is the police, investigating a report that
A shriek had been heard by a neighbour during the night; suspicion of foul play had been aroused; information had been lodged at the police office, and they (the officers) had been deputed to search the premises.
From that point, the narrator explains that the old man is away--"absent in the country"--and that he had made the noise himself, the result of a dream. He leads the police about the house, shows them that the old man's treasures are intact, and then brings them chairs in which to sit. The narrator, "in the wild audacity of my perfect triumph," places his own chair directly above the old man's body.
Soon, the narrator "fancied a ringing in my ears"; it grows louder and he soon realizes the sound "was not within my ears." He turns pale, gasps for air, and soon begins arguing with the police. He paces the floor:
I foamed—I raved—I swore! I swung the chair upon which I had been sitting...
but the sound grows "louder--louder--louder!" The narrator believes that the police are mocking him, and he can no longer restrain himself. He admits to the crime.
“Villains!” I shrieked, “dissemble no more! I admit the deed!—tear up the planks! here, here!—It is the beating of his hideous heart!”