This is an impartial, true life story, about the cold blooded murder of a rural farming family in Kansas.
The Clutter family lived a hard, but uncomplicated, life, and were well respected in the community, and as far as anyone knew, had no enemies. One night they were tied up and murdered each with a single shotgun wound to the head. This shocked the local community to the core, and traumatised the people who discovered their bodies. The local KBI set about trying to establish a motive, as virtually nothing was stolen, and trying to find the killers of this family. The main lead was given by a guy who was serving time, who remembered a conversation with a fellow inmate, and passed those details onto the police. Smith and Hickock, the accused, were apprehended when they made the mistake of returning through Kansas. They were arrested for parole violations and then were accused of the murders.
What Capote does here is to write a step by step account of the process. He does not judge the two accused, merely reports the facts, and lets you the reader make your judgement to the horror of the murders, the carefree attitude of the accused and the shock of the local community. The interrogation and the trial and subsequent convictions are covered in the same dispassionate style. At no point are you aware of his opinion or feelings towards the family and the accused.