This is more a theory and pieces fo a puzzle than a guess
1) There is the phrase "He is Ma..." Usually when someone knows a person or is trying to give clue they just write or say the name. A phrase written like this is when someone is giving a description or telling something about someone. I've always thought it could be "He is masked."
2) On the last episode Episode Kirkland kills the guy in the hospital but first asks him if he recognizes him. Even with a no answer the guy is killed.
I'm not saying Kirkland is RJ. In fact I find that too obvious a guess. But that doesn't mean that part of RJ's group, etc doesn't go around with disguises. I don't think they are going Scooby Doo on people but would it be outside the realm that maybe it isn't a male but a female in disguise? That would open things up. Or if it is a male, a disguise would allow one to be close to the police and have inside info and then also do their own thing outside of that realm.
I just think there is more to "He is Ma" and that it is a description more than a person.
