No character we have seen in the series is Red John.

This season they have shown us they are pretty much okay with doing flashback episodes that present us with characters that have never appeared on the show before.

All the clues they give, the shaking hands, books and rhymes, it doesn't have had to be shown on the show.
I think they will just keep writing for the character of Red John, completely unrelated to his "real identity".

If the show gets cancelled and they feel like they owe us an episode that concludes everything, they can write Red John in and build a flashback-episode around him and show us 'unseen footage' featuring Red John.

To be hones this a brilliant way to keep the series engaging, one of the worst things that happens to drama series is trying to steer it too much.

I think it is the DA Osvaldo Ardiles.  He is not quite six feet tall, not muscular nor flabby, he has the same build as the Red John who saved Jane from the fake red john movie makers, when Jane was tied to the chair, in "Red Sky in the Morning."  He is intelligent, and has access to restricted police computer systems and case information. I think it could be him. He would be in a perfect position to see if any warrants were to issued for any of his disciples. He was one of the four suspects in the  murder of Todd Johnson who was set on fire in custody at CBI, and the way that Rigsby tried to give the hint  to Ardiles as to where Hightower was, it was lame and besides O'Laughlin had received a better tip from Rigsby. As a DA, he can talk to any person involved with the Red John cases and not seem suspicious.   

Please stop with theory about PJ's double personality!!

-Rosalind should have recognized his voice, his build

-Who saved PJ from fake RJs?

-Lot of people were with him when he was chasing RJ in Mexico

-Lorelai said that he had already met RJ. how did she say so if she knew who RJ is truly?

In this theory there are too many inconsistencies

The theory about Summer as RJ is much more plausible, and that's saying something!!

In the season one finale, “Red John’s Footsteps,” they find
Red John’s lair.  Red John escapes, BUT his fingerprints and DNA (he was drinking a cup of tea) would be all over the house. They
also know he was building something (he ordered supplies), he hung out with his
old partner’s son (the town sheriff), he hung around a small town for at least 5
months, and he sometimes picked up mail at his PO Box.  That seems like more than enough to catch him,
especially for Patrick Jane.   I mean they have his DNA, right!?!

Go back and watch that episode. Can you really imagine Bret
Stiles, Walter Mashburn, or Bob Kirkland hanging out in that dilapidated farm house?



Also, if they have Red John’s fingerprints and DNA, but
haven’t caught him, that means he isn't in the system. That means he can’t work
at the CBI or any other government agency.  



Remember when Red John was just a serial killer. Yeah, me
too.