People might have personal reasons not to throw someone's real name around. Anyways it's THEIR choice not to name someone and their choice should be respected.
Ok, I am not saying that I don't respect it. They don't want to tell, that fine with me. It's just that my curiosity is overwhelming: there are those 2 books by Graham Johnson about organized crime in Liverpool but almost everybody is covered by a pseudonym. I was only told that "The Banker" is Philip Glennon, "Kallas" is James Taylor and "Fred the rat" is Tommy Comerford.