The writer gave us one too many clues. The Chief of the who CBI is the guy. Near the end of a recent episode, he quoted a line from a William Blake poem. The bald headed guy who has replaced Hightower informed Jane that the quote was a William Blake line when Jane asked. No big deal there. BUT, guess who wrote the poem "Tiger Tiger" burning bright??? WILLIAM BLAKE. Ergo, the boss is either Red John's inside guy, or he is actually RED JOHN. I am betting he is Red John. Cheers!!!

Grace Van Pelt. The entire series is based on the bad guy being somebody we've known from the beginning, and often is who we expect last. The most innocent seeming person. Here are some of my reasons. Lamest reason, she has red hair. Better reasons - She's the newest member of the CBI. (And Red John has already proven s/he can get into the CBI) Jane suspects she is hiding a 'deep emotional trauma'. Something she won't even admit to herself. Serial killers often have some kind of trauma, a messed up childhood or abusive ect, (at least in these cop shows I can't vouch for real life) and most often they create a world around them where the trauma did not exist. :D She is dating a killer at one point. I don't think that was accidental. She has Rigsby. If I were Red John, in the CBI, I'd want at least one gun who I knew could not shoot me no matter what. She's been purposely stringing along Rigsby too, blowing hot and cold in amazing ways. Unreasonable even for PMS. She is always challenging what Jane believes. She's the last person I'd expect, which makes her the most likely by the show's standards. Red John needs an in at the CBI so it makes sense. Red John WANTS to be close to Jane. Grace is always noticing things and holding back. Jane often calls her out to announce these things. It's like she's trying to hide how smart she is. Grace hesitates when Lisbon announces they are off the Red John Case. She also says that as a CBI agent they are quote 'fighting evil and injustice' something cop shows are famous for having serial killers disillusioned as. Grace also seems to try too hard to seem ignorant

I saw some theories that some people think it might Be Janes Father. I had an interesting idea hat its possible jane and Red John could be brothers or half brothers. Where is Janes parents anyways? Does anyone know where his father is? Did I miss a clue on the subject?Sometimes I thought at one point Bret stiles might be Red Johns Father.

I can definitively rule out the Mentalist Jane as “Red John” as he could not have poisoned somebody in a uniform and then 30 seconds returned from a distance and a staircase, in a suit, to tell then not to touch her. Physics rules. But, this still points to Minelli as the “uniform” that past by was a heavy armed individual that she looked up to slightly, not so much taller than herself, as is Minelli was only an inch or so taller than Lisbon, who seemed to be the same height as the “Red John” Secretary/Lover.

ok, so i just finished season 2.
i have to say im kinda pissed. although i knew once it got later in the season without many redjohn episodes i figured we still wouldnt find out who he/she was.
this show hasnt ALWAYS been super predictable, but sometimes it has. i mean just going off of the last episode. when jane was is marleys room and the forensics guy came in ANYONE watching the show could see that they wanted to make us think it was him. i dont want to believe thats true cause its kinda lame if it was. i agree with a lot of you here, RJ was small maybe the voice was a little feminine but i dont think it was frye. although i do think she is involved in some way. i sometimes played with the thought that maybe it was someone on the team. not cho cause they did that whole episode on him and i just dont see it being him. but no one really fits the part. well i hope we find out soon cause im getting anxious i dont know if i can sit through another season and not find out.