The premise is really nice. I enjoyed the 'he said she said' narrative, although going back and forth among the suspects/witnesses became tiring overtime. I think the ending is well thought-through even if some elements seemed out of nowhere. What I struggled with the most is the constant repetition - a conversation happens then we move to another person and we have to summarise the previous conversation so we repeat what was said and so on and so forth in following chapters (over 600 pages). It slowed down the pace to a crawl, successfully taking out any suspense.