A group of Mr. Clutter's old hunting buddies goes to clean up the house, considering it their "Christian duty." Meanwhile, the KBI, begins its investigation. Alvin Dewey is in charge. Dewey has no clues, save for a footprint and a missing radio. He suspects more than one murderer was involved. He is unsure of motive, because there was little money in the house that could be stolen. Also, he guesses that the murderers were close to the family because they seem to have known the layout of the house. Mr. Clutter was tied down in the furnace room, his neck was slit, and he was shot in the head. Kenyon was tied down to a couch in the basement rec room and shot, while Nancy and Mrs. Clutter were tied down and shot in their respective beds.
Paranoia and mistrust spread through Holcomb. The Clutters were perhaps the most secure, upstanding family in the community. No one now feels safe.
In the town of Olathe, Perry and Dick are eating in a diner. Dick has a ravenous appetite, but Perry eats little. He is worried that they will be caught. He gets Dick to admit that he had some incorrect information.
Susan Kidwell attends the Clutter funeral service. She remembers Nancy and her pet horse, Babe. She sees Nancy in her coffin, her head surrounded with cotton. A thousand people attend the funeral.
Dick and Perry move from shop to shop in Olathe, writing hot checks, and sometimes getting cash back. Soon their car is full of items that they can pawn.
Back in Holcomb, Dewey cannot sleep because his phone is constantly wringing. Everyone has a "tip," and each tip must be thoroughly investigated. His wife, Marie, wonders if they will ever have a normal life again.
The younger of the two surviving daughters is married on the next weekend. Her wedding had been planned for the following month, but as the entire family was already in Holcomb, the wedding date was changed. Also, a letter from Bonnie Clutter's brother, Mr. Fox, appears in the local paper, asking the townspeople to forgive whoever killed the Clutter family.
Perry and Dick are standing on a mountain outside of Mexico. Perry admits to Dick that he is surprised he was able to go through with the killings. Previously, he had told Dick that he once killed a black man for no reason, but this was a lie. As they continue on their drive, Dick continually swerves to kill stray dogs.
Back in Holcomb, the journalists have left, but gossip still thrives in Hartman's Cafe. One resident, a Mr. McCoy, has decided to move away, because his wife is so scared she cannot sleep. The Ashida family is also leaving.
This is the beginning of the hunt for the killers. It will occupy most of the book, and seems the most open-ended section of the novel, even though it is in the middle. The main plot lines at this point involve Perry and Dick's ability to get along and remain solvent, and Dewey's attempt to solve the mystery.
Perry and Dick have a peculiar relationship. Perry worries about getting caught, and this upsets Dick, yet in many ways, Perry is the more responsible of the two. Perry and Dick eventually become very poor because Dick is bad with money--he spends it on drinks and prostitutes. Dick pretends to be levelheaded, especially when Perry begins to discuss his dreams of the giant parrot, but Dick is responsible for getting the pair into trouble. After all, he invented the Clutter scheme.
Dewey becomes a very important character. In many ways, Dewey symbolically represents Capote. Like Capote, Dewey becomes very involved in researching the case. His desk fills up with notebooks. He loses himself in the case to the point that he cannot sleep. The same things happened to Capote, who felt psychologically damaged after completing the book. One is reminded of Dewey's wife's question about whether his life will ever be normal again.