"In Cold Blood" is a song by British indie rock band alt-J. It is the second track and second single from their third studio album, Relaxer, and was released as a digital single on 29 March 2017 by Infectious Music and Atlantic Records. The song was written by Joe Newman, Gus Unger-Hamilton, and Thom Sonny Green and produced by Charlie Andrew. It features a brass section recorded at Abbey Road Studios in London and a Casiotone the band purchased for £1.05 on eBay. The song's title is a reference to the novel of the same name by American novelist Truman Capote. The song's composition dates back to when the band started during their studies at the University of Leeds.