Pistone's dirty. There's no doubt about it. He admits in his book that if it came down to it, he would've killed for the guys he was with, all to save his own ass, knowing it's against the law and FBI protocol and would've immediately gotten him pulled from the operation and most likely indicted on murder charges. That or with him being well-liked after all his years of productivity, they would've placed the murder on some other mob guy.