Question: Richard Brooks adapted the work of which author for his film In Cold Blood?

Context paragraphs:
The Brothers Karamazov (1958 film): The Brothers Karamazov is a 1957 film made by MGM, based on Fyodor Dostoevsky's novel "The Brothers Karamazov".  It was directed by Richard Brooks and produced by Pandro S. Berman.  The screenplay was by Julius J. Epstein, Philip G. Epstein and Richard Brooks.  It was entered into the 1958 Cannes Film Festival.  The brothers are played by Yul Brynner, Richard Basehart and William Shatner in his film debut.

The Last Hunt: The Last Hunt is a 1956 MGM western film directed by Richard Brooks and produced by Dore Schary.  The screenplay was by Richard Brooks from the novel "The Last Hunt", by Milton Lott.  The music score was by Daniele Amfitheatrof and the cinematography by Russell Harlan.

In Cold Blood (film): In Cold Blood is a 1967 film based on Truman Capote's book of the same name.  Richard Brooks prepared the adaptation and directed the film.  It stars Robert Blake as Perry Smith, Scott Wilson as Richard "Dick" Hickock, and John Forsythe as Alvin Dewey.  The film follows the trail of Smith and Hickock; they break into the home of the Clutter family in Holcomb, Kansas, kill all four members of the family who are present, go on the run, and are found and caught by the police, tried for the murders, and eventually executed.  Although the film is in parts faithful to the book, Brooks created a fictional character, "The Reporter" (played by Paul Stewart).  The film was nominated for four Academy Awards: Director, Original Score, Cinematography, and Adapted Screenplay.

Cold Blood (band): Cold Blood is a long-standing R&B horn funk band founded by Larry Field in 1968 and was originally based in the East Bay region of the San Francisco Bay Area.  The band has also performed and recorded under the name Lydia Pense and Cold Blood, due to the popularity of their lead singer, Lydia Pense.

In Cold Blood: In Cold Blood is a non-fiction novel by American author Truman Capote, first published in 1966; it details the 1959 murders of four members of the Herbert Clutter family in the small farming community of Holcomb, Kansas.

Cat on a Hot Tin Roof (1958 film): Cat on a Hot Tin Roof is a 1958 American drama film directed by Richard Brooks.  It is based on the Pulitzer Prize-winning play of the same name by Tennessee Williams adapted by Richard Brooks and James Poe.  One of the top-ten box office hits of 1958, the film stars Elizabeth Taylor, Paul Newman and Burl Ives.

Fever Pitch (1985 film): Fever Pitch is a 1985 American drama film starring Ryan O'Neal, and written and directed by Richard Brooks.  This turned out to be the final film for Brooks, director of such acclaimed pictures as "Blackboard Jungle", "Elmer Gantry", "Cat on a Hot Tin Roof" and "In Cold Blood".  Co-starring in the film were Giancarlo Giannini, Chad Everett, John Saxon and Catherine Hicks.  The original music score was composed by Thomas Dolby.

In Cold Blood (Johnny Thunders album): In Cold Blood is a 1983 double album by Johnny Thunders.  The "In Cold Blood" album contains studio recordings and the Live LP contains live recordings.

Richard Brooks: Richard Brooks (May 18, 1912 – March 11, 1992) was an American screenwriter, film director, novelist and occasional film producer.  His outstanding works as director are "Blackboard Jungle" (1955); "Cat on a Hot Tin Roof" (1958); "Elmer Gantry" (1960) – for which he won an Academy Award for Best Writing (Adapted Screenplay); "In Cold Blood" (1967); and "Looking for Mr. Goodbar" (1977).

Thriller (Cold Blood album): Thriller is a 1973 album by San Francisco funk group Cold Blood.  Lydia Pense and the rest of Cold Blood were backed by The Pointer Sisters.

Supporting paragraphs: Fever Pitch (1985 film) In Cold Blood
Answer: Truman Capote