I'm sorry to say this was quite disappointing. It was all over the place, in all aspect.
The first half of the novel followed any possible character (some only minimally related to the mystery). A lot of space concerned the MC'S coming to terms with what happened in the previous book.
The murder happend halfway through the book. At that point the story was gripping for a few chapters... then went all over the place again. The ending was messy.