Sequel to the book

It's called "Northwest Corner" (by John Burnham Schwartz)and takes places 12 years after the events in "Reservation Road." Dwight served 2.5 years in prison and now lives in California, managing a sporting goods store. He hasn't seen or spoken to Sam in all those years until his now-grown son suddenly shows up on his doorstep, needing help.

Other characters from "Reservation Road" make an appearance, but I won't spoil it for you.

For those who wonder what happened to Dwight and the others, it's a good read.