Part 4, Chapter 5: Lebeziatnikov tells them that Katherine has gone out of her mind. After being evicted, she ran off to find Marmeladov's former boss, who was at a business dinner. They threw her out and she was threatening to take the children out onto the streets to perform for money. They rush out of the house, Sonia leading.
Outside, Lebeziatnikov confides to Raskolnikov that the tuberculosis has caused Katherine's mental breakdown. When they pass Raskolnikov's house, he goes inside and looks out the window, thinking. Dunia enters. She tells him she has heard about the false suspicions he has endured and that if he ever needs her, she'll come. She turns to leave, but he stops her and tells her that Razumikhin is a good man and capable of loving deeply. When she leaves, he reflects that if he had embraced her, afterwards she might remember it and shudder.
Suddenly, Lebeziatnikov appears and informs Raskolnikov that Katherine has indeed taken to the streets with her children. She is completely mad and alternates between instructing the children on song and dance and beating them. When they find her, Sonia is begging her to come home and weeping. Katherine refuses to leave, saying, Let all Petersburg see how the children of a decent father beg for alms. Finally, two of the small children break away and run and Katherine follows. She stumbles and falls, and blood comes spurting from her lungs. A policeman helps carry her to Sonia's place, where she dies, half-delirious, crying, They've finished off the old nag! She's...overstrained! In the midst of the chaos, Svidrigailov had turned up. He approaches Raskolnikov and tells him he will pay for the funeral and put the children in the best orphanage he can find. He further plans to set aside a thousand and a half rubles for each child for when they come of age and will pull [Sonia] out of the mud too...You can tell your sister that's how I used her ten thousand. When Raskolnikov asks why he is doing this, Svidrigailov responds by repeating some bits of the conversation he had had with Sonia, thus revealing that he been behind the partition the whole time and had heard everything.
Part 6, Chapter 1: A strange time began for Raskolnikov, during which he brooded and grew anxious. In later recollection, it seemed like his consciousness kept flashing on and off. He worries especially over Svidrigailov, whom he does not trust. He does not attend Katherine's funeral.
Razumikhin comes to see him and tells him that Dunia had received a letter today that upset her very much. He also says that they caught the murderer, referring to the painter. When Razumikhin leaves, he is thinking about how his previous notion about Raskolnikov had been nasty and vulgar and that Nikolay's confession would bring everything to light. Thus, Razumikhin had consciously entertained suspicions that Raskolnikov was the murderer.
Raskolnikov now wonders whether Razumikhin suspects him. He decides to go out but bumps into Porfiry when he opens the door.