How does Capote pieces together the murder

When Capote learned of the quadruple murder, before the killers were captured, he decided to travel to Kansas and write about the crime. He was accompanied by his childhood friend and fellow author Nelle Harper Lee, and together they interviewed local residents and investigators assigned to the case and took thousands of pages of notes. The killers, Richard "Dick" Hickock and Perry Smith, were arrested some six weeks after the murders, and Capote ultimately spent six years working on the book.