In Cold Blood tells the true story of the murder of the Clutter family in Holcomb, Kansas, in 1959. The book is written as if it were a novel, complete with dialog, and is what Truman Capote referred to as "New Journalism" — the nonfiction novel. Although this writing style had been used before, the craft and success of In Cold Blood led to its being deemed the true masterwork of the genre. For Truman Capote, it was the last in a series of great works, which included Breakfast at Tiffany's, Other Voices, Other Rooms, and The Grass Harp. In Cold Blood was originally published in four parts in The New Yorker and then released as a novel in 1965. In Cold Blood took six years for Capote to research and write, and it took an incredible toll on Capote, personally — so much so that he never published another book again. In Cold Blood is said to have been his undoing.
The book tells the story of the murder of the Clutter family, consisting of Mr. and Mrs. Clutter and their two teenage children, Kenyon and Nancy (two older daughters were grown and out of the house), and the events that lead the killers to murder. The family was living in Holcomb, Kansas, and in November 1959, they were brutally killed, with no apparent motive, by Dick Hickock and Perry Smith. The family was discovered bound and shot to death, with only small items missing from the home. Capote read about the crime in The New York Times soon after it happened, and before the killers were caught, he began his work in Kansas, interviewing the people of Holcomb and doing extensive research with the help of his friend Harper Lee, who would go on to write the classic To Kill a Mockingbird.
Perry and Dick initially get away with the murder, leaving behind scant clues and having no personal connection with the murdered family. Capote explores the motive again and again within his text, eventually concluding that any real motive for the crime lays within Perry — his feelings of inadequacy, his ambiguous sexuality, and his anger at the world and at his family because of his bad childhood. Dick plays the role of true outlaw, but the impact of the killings weighs heavily on him, and his own role in the murders remains unexplained and unclear.
The townspeople of Holcomb and other friends of the Clutters are deeply affected by the murders. This includes Nancy's best friend, Sue, and Nancy's boyfriend, Bobby. The townspeople perceived the Clutters as the family "least likely" in the world to be murdered. Unable to conceive that the killers were strangers, many of them become suspicious of everyone and anxious about their own safety in the company of their neighbors. The man who heads the murder investigation, Al Dewey, becomes obsessed with both the murderers and the Clutter family. His need to find the killers becomes his driving force in life.
While the anxiety in Holcomb grows, the killers move on with their lives. The book follows Perry and Dick to Mexico and back, and incredibly, it seems that they might never be found out and brought to justice. Ultimately, a living witness who can tie the two men to the Clutters, footprints at the crime scene, and the possession of a pair of binoculars and a radio from the Clutter home become the pair's undoing. They are arrested and both confess to their part in the crime. They are tried for murder and convicted; after many years on death row, both men are hanged. During their time on death row, Perry slowly reveals his personal thoughts, his ambitions, and the motives that contributed to his life choices, including the fateful night he and Dick entered the Clutter home.