That night Tom and Huck take the dead cat to the graveyard, where there they hear voices belonging to Muff Potter (the town drunk), Dr. Robinson, and Injun Joe. Dr. Robinson has paid Muff Potter and Injun Joe to dig up the corpse for his medical research. After a fight between the three men, in which Muff Potter is knocked unconscious, Injun Joe stabs Dr. Robinson with Muff's knife. Huck and Tom flee and do not hear Injun Joe convince the drunken Muff that he is the murderer.
Tom and Huck run to the old tannery, where they discuss the dilemma they're in. They both realize that if they reveal Injun Joe as the murderer, he will kill them. The boys take an oath to not reveal what they have seen. Suddenly, they hear a stray dog barking. Thinking it is an evil omen, both boys temporarily renounce their wicked ways.
By noon the next day, the entire town of St. Petersburg knows about Dr. Robinson's murder, and they know that the murder weapon was Muff Potter's knife. School is dismissed for the afternoon, and everyone gravitates to the graveyard, where the sheriff is with Muff Potter, who initially proclaims his innocence. But finally, in despair, Muff tells Injun Joe to reveal the truth. Injun Joe, of course, makes sure that all of the guilt is placed on Muff Potter.
Listening to Injun Joe's lies and machinations, the two boys begin to feel conscience-stricken about their silence. Tom's conscience bothers him so much that he eases it by "smuggling small comforts" to the prisoner, but he can't escape his conscience altogether. At night, he is troubled by wild dreams, and he often talks in his sleep about blood and murder and graves, but his mumblings make no sense.
