In terms of structure the third part half fullfils a promise made to the reader. That promise being made is that the case will be solved. When I saw structure I’m referring to Orson Scott Card’s M.I.C.E. Quotient. For more information you can read How to write Science Fiction and Fantasy or check out a Writing Excuses podcast on the subject.
This story being primarily a mystery means that it’s an event story. Of course the first scenes we get are about the characters. The “C” in “M.I.C.E.”
Mary Robinette Kowal talks about how this quotient is like html code. The code for The New York Crimes might look something like this:
A crude example, but I hope it gets the message across. Anyway the reason I bring this up is because the fulfillment of the “idea” aspect seemed tacked on. I’m glad the writer didn’t skip it entirely. It would be like never finding out who the murderer is in a classic whodunit story. This is a problem that The Dark Knight Rises has with its villain. People who have seen the movie probably know what I’m talking about, so I won’t go into any detail for spoiler reasons.
The cliffhanger ending works as we wrapped up the idea aspect and now, based on the final scene at the bar, in the next part we will be wrapping up the character aspect.