I just finished "In Cold Blood"

It took me in total 2 days to read, which is pretty fast for me, as I'm a slow reader and most of the books I can't even finish. But I didn't get bored or distracted in the time I was reading it, I guess Capote's is very talented at storytelling. I still don't fully know how it captivated me so much LOL. Few good things I can think of: The two parallele timeline narrative makes the story more lively, the reader can observe both at once so the tension is building even when describing the happy life of victim family; and there are a lot of well-established characters, there personalities and interaction with people around are nicely described, but not too long to shift the focus; the psychological problem of Perry is intriguing and horrifying, makes one think "how could a seemingly kind person does something so brutal and senseless, do trauma and narcissism really numb people from compassion?" But there are more to it I can not capture! Curious to know what's your experience with the book! And what do you think that makes the writing so good?