"The Jungle Book" theory.
Famous Rudyard Kipling has a story collection called "The Jungle Book". I suggest you all to pay attention to its chapters 5 and 9. Chapter 5 is called... surprise... "Tiger! Tiger!". Chapter 9 is called "Rikki-Tikki-Tavi". It's about a pair of antagonistic cobras named Nag and Nagaina.
So, I offer that there is also a female RJ or "Red Joan". I'm not going to suit all the clues for this suggestion, but even the "He is Mar..." makes sense. RJ was McAllister. When I heard Kirkland's story about his brother, I made a guess that RJ must be one of the elder suspects - Stiles, McAllister, maybe Bertram, and among these McAllister was the most probable one. Besides, we were shown several times how somebody escapes some scenes on police car (for example, you may rewatch the last couple of minutes of season 4). Understanding and sharing all the unsatisfaction about S06E08, I have to conclude that McAllister was RJ with a very high probability.
But, as I said, there must be another "tiger" as well, or "tigress", to be correct. We know that the concept of criminal couples is highly connected to RJ. At this point I can't present a full theory, but we may discuss some female characters and create a new "list of 7". I suggest:
1) Madeleine Hightower. Helping to catch a man who is chasing RJ is the very right thing to do for this "tigress". On the other hand she might be more Bagheera.
2) Kristina Frye. We used to see her doing some extraordinary thing. But this kind of Frye simply could not exist, and PJ thinks the same way. So we have a character that can't exist, and may be hopeful to get some revelations about her true methods.
3) Rosalind Harker. RJ was using everybody he had in his "friends", and they all were useful. Perhaps the only exception is Harker. Sorry, but she is just useless for RJ. So either RJ truly loved her, or she is not just what she shows. On the other hand, she might be the key to one of the hardest mysteries: how RJ got the list? Everybody was criticizing PJ about the fact that he hadn't tried to check the voice recordings of the suspects with Frye to identify RJ. Actually we can't be sure he hadn't.
4) Lorelei Martins. If the previous thought about how RJ could get the list is true, then Martins had to be alive. Her death could be faked because of Partridge playing on RJ's side. Not a big fact, but when she was ordered to cut PJ's two fingers she chose the finger with a wedding ring. If she is the "tigress", then she was engaged in her sister's murder. She was playing like she is going to take a revenge, and later Lennon could enlighten this situation but was killed in hospital by M.Kirkland, who asked him a question to be sure he hadn't told anything to his twin brother Bob. Another fact is the shaken hands. First, I can't imagine RJ telling somebody about a simple handshake. It should be a special shaking, deserving to be mentioned. So, one more point for McAllister to be RJ. And second, RJ could share information only with somebody very close to him, like a wife.
5) Kim Fischer. Not much to say about this character yet. But her undercover actions and skills of putting ideas into PJ's head are very promising.
6) Ellen Preston. What a list without a forgotten character? Ellen Preston was the woman involved in "The Red Barn" story. It's supposed that RJ killed Talbot and Charney, who were running the farm. They were in conflict with Ellen Preston, so maybe RJ's probably first two murders were made to protect Ellen or her daughter, Holly Preston. Both could be love interest for young RJ.
7) Woman from the chapel. What a list without the second minor character? First, we were shown how this woman escaped before FBI reached the chapel, and this means she is still active. Second, the knife she was wearing was stupid but classic for criminal couples (one with a gun and another with a knife). Third, Gupta mentioned RJ being religious, it's also mentioned Tim Carter's connection with missionary in Africa, and McAllister being a big lover of hunting. So maybe McAllister was on safari and his wife (as I remember, RJ had a ring) was serving at church (and by this sourcing RJ with new suitable recruits). And forth, if RJ was PJ's reflection, then this "tigress" should be Lisbon's reflection. The actresses playing Lisbon and this mysterious woman are Robin Tunney and... one more surprise... Susan Tunney (actually not sure about this fact, because the role "Woman" mentioned in IMDB may refer to another character).
P.S.: If you read this http://en.wikipedia.org/wiki/T... you may find some similarities with the mentalist story.
P.P.S.: In "The Second Jungle Book" there is a story called "Red Dog".