Kaltblütig.

I liked the novel and because of it watched the movie about its author. "On November 15, 1959, in the small town of Holcomb, Kansas, four members of the Clutter family were savagely murdered by blasts from a shotgun held a few inches from their faces. There was no apparent motive for the crime, and there were almost no clues." Quote from the back of the book.