Book is even better than the movie
And I love the movie.
Just read the updated version with the last section that tells you what happened with the main characters afterwards. The writing is compelling.....more a novel than a well-researched and documented investigative piece (which it is as well). Also has much more detail than you see in the movie. Could not recommend more.
Could spoil on some of the personal histories of the main character, but that just wouldn't be fair.