I strongly feel that Patrick Jane is Red John!! Split Personality Disorder and master of hypnotism.

When his wife found out that he was a serial killer apart from being the conman, he killed her and his daughter (or whether they were his real family we don't know!!).
He never wants Christina Frye to be on a case as she is a self confessed Psychic and maybe he feels that if she tries to get closer to Jane through the cases that they work together on then she might be able to find out the secret of his.
All the people who entered in CBI as an accomplice to Red John were hypnotized by him to an extent that they were willing to give their lives for Red John (the lady who killed the cops including Sam Bosco and Craig O'Laughlin).
There are many more theories which could easily confirm that Jane is RJ but we will wait and see.

I seriously wish that I am wrong as that would make my watching Season 4 n 5 more exciting :). Cheerz!!