From what I recall from the book, Castelli got into an argument with some guy outside a restaurant and was killed. Franceschini didn't think it was related.

And yes, Manna is serving time for Schiff. If you actually dig into that whole Schiff thing, it's very interesting how it played out for everyone involved- how they used Schiff's girlfriend to "identify" the killers and the methods they used to get her to change her story from the original one she gave, the alleged tape recordings that were not clear that the govt claimed was more proof that Manna was involved. It raises a lot of questions.