Its pretty obvious that Kristina Frye is Red John. She makes the only sense in the entire show. The other characters have no weight or legs to stand on to be Red John.

Pretty sure Patrick Jane's 7 member list definitely has Red John's accomplices on, but she is the puppet master stringing them along.

I read a submission somewhere here where the submitter spoke about the He Is mar - and that Jared Renfrew meant to write He Is marionette (The definition of Marionette - A marionette is a puppet controlled from above using wires or strings depending on regional variations. A marionette's puppeteer is called a Manipulator).
Remember Jared didnt know who Red John was, but only said that he had really important information on Red John.

She makes the only sense if you have watched the entire series, and add it all up.

She is the only character who as shown similar mental superiority to Patrick
She also mysteriously disappeared during the Season 2 finale and conveniently Red John shows up to save Patricks life from the student filmmakers/copycat killers., recites a Tyger,Tyger poem and then leaves Patrick with the Rolltide statement.
Also when she disappeared from heavy police protection, her passport was taken as well. (Why would Red John do that if she wasnt Red John)
She as survived the fatal on TV dissing of Red John
She shook Patrick's hand
She knows that Patricks daughter was asleep when she was killed (Psychic powers come on - she was there so she knows)
Painting of toenails is definitely a women's thing
She has not been present in the show for a while, so this would be a major twist. A writers method of getting viewers to forget about a character so that it would be a major surprise when Red John is revealed.