The Clutter family – Herbert and Bonnie, and their teenage children, Nancy and Kenyon – lead a prosperous and principled life on their farm in Holcomb, a small rural settlement in western Kansas. They are prominent and respected members of the community, in both Holcomb and the neighboring Garden City, and Herb Clutter is known to be a generous employer. Their life is disciplined, but pleasant and well provided for. The narration follows the Clutters through the events of November 14th, 1959, which is ominously referred to as the family’s “last.” In another part of Kansas, two men on parole from the Kansas State Penitentiary, Dick Hickock and Perry Smith, are planning a “score,” which includes a 12-gauge shotgun, rubber gloves, rope, and black stockings. Over the course of the day, they make their way in the direction of Garden City by car, making various stops along the way. They arrive shortly after midnight, and proceed to the Clutter farm.
On the morning of November 15th, two friends of Nancy Clutter’s arrive at the house and find Nancy upstairs, dead from a shotgun blast to the head. The authorities, in turn, find three more bodies: all four Clutters have been brutally murdered, the children and Bonnie with a shotgun, and Herb Clutter with a knife to the throat. The police find very little evidence at the crime scene: only two sets of boot prints, and the materials used to bind the victims. The residents of Garden City and Holcomb are shocked and deeply troubled by the murders, and many speculate that the killer or killers may be among them.
An investigation is launched, led by Alvin Dewey. The team also includes Special Agents Clarence Duntz, Harold Nye, and Roy Church. Perry and Dick are already far away in Kansas City, reading about the crime in the newspaper and wondering about the likelihood that it will be traced to them. While the detectives begin their search for physical evidence and witness testimonials, the fugitives head for Mexico, pausing only long enough to earn some quick cash by dropping bad checks in Kansas City.
Details about the murderers are slowly revealed in the course of the narration. Perry dreams of grand adventures and of being whisked away from his troubles by beautiful parrots; his escapist reveries are a way of compensating for the trauma of his childhood and his degraded lifestyle. He is self-conscious, sensitive, and philosophic. Dick, on the other hand, is cocky, self-assured, and pragmatic; financial irresponsibility has led him away from a solid upbringing to a life of petty crime. His ambitions are also a way of compensating for his lack of means, but his bluster and bravado stand in sharp contrast to Perry’s demure presence.
The investigative team receives its first lead in the form of Floyd Wells, a former employee of Herb Clutter’s who celled with Dick at the Kansas State Penitentiary, and who told Dick that the Clutters kept a locked safe full of cash in their home. The detectives follow up on Wells’ testimony, and discover that both Dick and Perry were traveling on the night of the killings. Meanwhile, the fugitives have returned to the United States, and continue to roam the countryside, hitchhiking. Eventually, the police trace a stolen car to them, and they are apprehended in Las Vegas just before New Years’, six weeks after the murders.
During the interrogation, the detectives only gradually reveal that the two men are wanted for quadruple homicide. Catching Dick in a web of lies and false alibis, they succeed in forcing a confession out of him, but he blames Perry for all four murders. En route to Garden City, Agent Dewey convinces Perry, in turn, that Dick has confessed to the crime, and Perry, finally defeated, provides a lengthy account of how the murders transpired. According to Perry, their initial aim was to rob the Clutters, having heard from Floyd Wells that Herb Clutter kept ten thousand dollars in a safe inside the house. When they arrived and found no safe, nor anything else of significant value, Perry had wanted to abandon the scene, but Dick urged him to stay and follow through: "No witnesses." Trying to make Dick admit that he couldn't actually go through with the killings, Perry himself took up the knife, meaning "to call his bluff," but was seized by sudden emotion, and to his surprise found himself slitting Mr. Clutter's throat. The subsequent shootings all happened in a blind frenzy on the part of the killers, after which they fled the scene.
The men are put on trial in Garden City. In the course of the trial, the prisoners undergo a psychiatric evaluation, during which it is concluded that both show definite signs of mental illness and emotional dysfunction. Perry almost certainly suffers from paranoid schizophrenia, and Dick has brain damage incurred in a car accident as a young man. In the case of Perry, who has confessed to all four murders, the doctors conclude that the killings functioned as a form of unconscious retribution for all the misfortunes and disappointments of his life, beginning in his childhood. For Perry, the Clutters and their immaculate lifestyle symbolized everything the world had denied him, and their murders, beginning with Herb Clutter, were a quasi-automatic response.
In spite of these findings, the court upholds the M’Naghten rule, which disregards mental illness in determining whether criminals are responsible for their actions. Dick and Perry are found guilty of four counts of murder in the first degree, and sentenced to death by hanging. They spend five years on Death Row, where they are joined by Lowell Lee Andrews, Ronnie York and James Latham, all high-profile murderers. In spite of numerous appeals, as well as allegations of mistrial (from Dick), they are hanged on April 14th, 1965, before a crowd of twenty witnesses.
The last scene belongs to Alvin Dewey, who visits the cemetery where the Clutters are buried, and marvels at the persistence of life, even in the aftermath of such hopeless tragedy.
