In Cold Blood is a 1967 American neo-noir crime film written, produced and directed by Richard Brooks, based on Truman Capote's 1966 nonfiction novel.

It stars Robert Blake as Perry Smith and Scott Wilson as Richard "Dick" Hickock, two men who murder a family of four in Holcomb, Kansas.

Although the film is in parts faithful to the book, Brooks made some slight alterations, including the inclusion of a fictional character, "The Reporter" (played by Paul Stewart).

The film was shot on location at sites where Smith and Hickock's crimes occurred, including the real Clutter home where they robbed and murdered four members of the family.

In 2008, In Cold Blood was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".

In order to leave no witnesses to their robbery attempt, Smith and Hickock kill Herbert by cutting his throat, and proceed to murder his wife, Bonnie, and their two teenage children, Nancy, 16, and Kenyon, 14, with a shotgun.

After two weeks in Mexico, the two return to the United States, and decide to travel to Las Vegas, Nevada, hoping to earn money in gambling winnings.

Shortly after their arrival to Las Vegas, Smith and Hickock are arrested for driving a stolen car, violating parole, and passing bad checks.

[4] Otto Preminger had initially expressed interest in directing an adaptation, but Brooks agreed to the project and purchased the rights from Capote[5] for an estimated $400,000.

[6] Brooks' screenplay followed the structure of the book closely, shifting between Smith and Hickock and the Clutter family,[7] though slight details were included that were not present in the source material.

[6] Columbia Pictures originally wanted Paul Newman and Steve McQueen as Richard Hickock and Perry Smith, respectively, but Brooks refused as he felt their star statuses would render their performances less believable to audiences.

[10] In accordance with Brooks's desire to achieve as much realism as possible, some scenes were filmed in Garden City and Holcomb, Kansas at the locations of the original events, including the Clutter family's farm where the murders took place.

[13] Brooks's demeanor on set was noted as tempestuous by cast and crew members,[14] with Wilson recalling that he was "focused [and] inspired" but "unpredictable...  a volcano who was going to erupt at some point".

Bosley Crowther of The New York Times called the film an "excellent quasidocumentary, which sends shivers down the spine while moving the viewer to ponder".

"[19] Charles Champlin of The Los Angeles Times put it on his list of the ten best films of 1967, calling it "an honest, sobering, revealing motion picture, earnest and authentic, with only minor lapses into theatricality.

The site's consensus reads: "In Cold Blood is a classic docudrama with a fictional thriller's grip -- and a pair of terrific lead performances from Robert Blake and Scott Wilson".