Part 4, Chapter 3: Katherine, who is increasingly emotionally unstable, asks Luzhin to come to her aid, citing her father's hospitality to him. He waves her away contemptuously, openly denying that he knew her father. He goes immediately to Sonia and accuses her of stealing a one hundred-ruble note from his room during their meeting. Katherine rushes to her defense, vehemently denying that Sonia would do such a thing. Sonia is frightened and horrified. She responds that she didn't take anything and gives him back the ten-ruble note he had given her. Sonia looks around her in despair and sees the crowd eyeing her with hostility. Raskolnikov is gazing steadily at her. In anger at Luzhin's accusations, Katherine searches Sonia's pockets. In her right pocket she finds a crumpled one hundred-ruble bill. Katherine still does not believe Sonia is guilty. She gives a pathetic plea to the crowd to come to her aid.
Suddenly, a voice in the doorway says, How lowdown that is! It is Lebeziatnikov, who testifies that he had seen Luzhin slip the bill into Sonia's pocket and had thought at the time it was because he was doing a good deed. Raskolnikov immediately speaks up and spells out a motive, relaying the details of Luzhin's engagement to Dunia and how he had tried to put Raskolnikov in a bad light by slandering Sonia. Luzhin leaves and on his way out, someone in the crowd throws a glass at him but misses and hits the landlady. At this, she evicts Katherine and her family. Raskolnikov goes to follow Sonia, who had fled.
Part 4, Chapter 4: Sonia exclaims, What would have happened to me if you hadn't been there! Raskolnikov responds by telling her the incident was based on her social position. He then asks if it were for her to decide, who she would choose to remain alive, Katherine or Luzhin. She rebukes him for asking her something that shouldn't be asked. She keeps asking him what is wrong, sensing something horrible. He understands that she loves him, however, and struggles to reveal the truth. He reminds her that he had promised to tell her who had killed Lizaveta and asks her if she can guess. He turns to face her and says, Take a good look. After understanding, Sonia collapses with grief, but then goes to him and holds both his hands. Why, why did you take this upon yourself! she says and throws her arms around his neck. When he tells her she is strange for embracing him after he what he has told her, she says, ...there is nobody...anywhere in the world now unhappier than you! She says she will go with him to Siberia. He responds saying that maybe he does not want to go to Siberia and in that voice she hears the tones of the murderer.
Raskolnikov offers various explanations for his crime, but settles on I killed for myself, myself alone. Sonia instructs him to rise and go to the crossroads, to bow down and kiss the earth which he has defiled, then bow down to the four points of the compass and say aloud, I have killed. She says, You must accept suffering and redeem yourself by it. Raskolnikov still resists the idea of repentance and confession. Since Sonia had turned to him with all her heart he was more miserable. She offers him a cross made of Cypress and says she'll wear one of brass that was given to her by Lizaveta. At that moment, there is a knock at the door. It is Lebeziatnikov.