My theory is that Dignam went underground, doing his own little ruthless investigation into who capped his boss, and later his co-worker in Costigan...until Vera Farmiga gets him Billy's tapes....then he goes out for bloody revenge.
Yeah?
I agree Ronnie. After watching some idiots debate on whether or not Dignam was on the take, and a mob mole in his own right (Not here, on IMDB) I read the script online, to see if it mentioned Dignam's POV. It does, it reads that Dignam avenged the death of a cop that he "didn't even like", because it was the right thing to do. He just couldn't let him get away with it.
