In Cold Blood

Before reading In Cold Blood may I suggest you watch the 2006 movie Infamous? They work so well together, for the movie stops where the book begins - the final scenes in the movie are of Truman Capote at a cramped desk writing...
In the movie: "What starts out as the irreverent journey of the openly gay writer Truman Capote to the middle-class world of 1950's Kansas, where he goes--with his childhood friend Harper Lee--to research the murder of the Clutter family, turns to something altogether darker when Capote forms an intense and complex relationship with one of the murderers...."
Well, I'd never have guessed from the book alone that Capote was a gay man, or that he fell in love with Perry Smith. There's no trace of the author's private life in it. Or his personal feelings. Until I watched the movie I assumed In Cold Blood was kind to the killers because Capote had spent time with them, and got to know them as people; and that the dead Clutter family were harder to write because he never met them...
Now I realise the book is not a disinterested reconstruction of heinous mass murder and 'how the bad boys were caught'; instead it is a love letter and an apology to Perry Smith - for though Capote may have been in love with him, it didn't stop him bleeding Smith dry to get what he wanted for his book.