My opinion: Ray Haffner.
Reasons:
1-He likes/respects Jane (not like Bertram, for instance, that doesn't seem to appreciate Jane at the CBI, or Smith, who apparently doesn't give a s.);
2-He truly seems to like Theresa and call her by her first name;
3-He fits the profile, including the whole visualise/barn thing (he was a teenager at the time);
Now it gets interesting..
4-As mentioned in other theories, the actor who plays RJ says in the interview for TV Guide that he was surprised for being chosen - he thought he was a red herring. He also uses the expression "truth be told". It has been proven Reed Diamond (Haffner) also uses that frequently;
5-He hasn't the three dotted tattoo. You might be saying: that's the opposite of a lead! Some people already discarded Haffner as suspect because of that. The way I see it, anyone who has the dots is also a member of Tyger Tyger (a symbol of it). I don't believe at all RJ is a member of such organisation (more on that later). Therefore, it could be either Haffner or Stiles. Well, Stiles is dying, which, again in my opinion, pretty much eliminates him as a suspect (that and the fact that he wouldn't be in his 20s or so at the barn);
6-He is missing from this picture (before anyone starts criticizing, I know this is sort of a long shot): http://instagram.com/p/gjUXK7FnMM/ This picture was taken on Sun's episode, clearly after the suspects had shown their shoulders to Patrick. Why is Reed Diamond missing? Well, it could be nothing, but it could also mean something.
Now I'm gonna move to my actual theory of the plot.
I think RJ is not a part of Tyger Tyger. Instead his almost unlimited resources come from Visualise. As to why I don't think RJ belongs to the organisation, that's because Partridge, a probable member (Tyger Tyger before dying, as usual), was killed by RJ. As to why I think RJ belongs to Visualize, because Stiles, the church's guru, knows RJ quite well, apparently (I remember he mentioning Patrick's friend 'John' is quite powerful etc.). Guess who's the only one - besides Stiles - who belongs to Visualize on that list? Yup, Haffner. Seems kind of odd, right? Among the 7 original suspects, 3 definitively belong to Tyger Tyger, 2 definitively belong to Visualize, Brett Partridge is probably a member of the latter and Kirkland was trying to uncover the story behind this same organisation (BTW, I think that's the reason Smith killed him, and not because he knew something about Red John (which we probably wouldn't tell anyone but Jane)).
I also believe Visualize and Tyger Tyger are completely different entities, and do not have members in common (at least shouldn't). In fact, I think these organisations have some rivalry (they both have their fair share of illicit activities, one way or the other), which probably would have to do with Red John.
That said, I think Partridge got wind of the fact that he was being bugged by CBI's team and wanted to kill Theresa, confront her, tell Tyger Tyger; something along those lines. RJ killed him before he could do that to protect Lisbon (amongst other reasons) (vide item 2). That gives rise to the problem that Tyger Tyger then had also to be on the search for Red John. He, on the other hand, would've been able not to be caught by Tyger Tyger so far with help of Visualize.
If that's the case and Visualize and Tyger Tyger are rivals, it sort of explains why would RJ bomb PJ's house with 3 tyger tyger members (obviously, PJ and RJ definitively survive the explosion. If Stiles doesn't, that's because he was gonna die soon anyway, he probably arranged things with RJ to avoid suspicions). This also would explain why Smith was kind of astonished when Jane announced one of the five was RJ (a fact probably new to Tyger Tyger members, who would've been searching for Red John for a while now).
I hope any of this made sense to you guys, and I would ask that before you downvote my theory (I'm not saying that you shouldn't), just leave a comment saying why do you think I'm wrong. I think that's more useful to refining the hypothesis (or just throwing it completely away, if that's the case) than just downvoting it. Thanks.
Greetings from Brazil!
