Since I do not believe that RJ is any of the people from the list, I thought I would share one of the people that I strongly suspect.

Alex Jane

Does anyone else suspect Patrick Jane's father, Alex, to be Red John?

He would be one of the only people to really know Patrick and his past. Plus, he is the one who taught Patrick how to be a con artist and a mentalist, so he would know all of his tricks, causing RJ and Patrick to think and be alike.

- He was said to be abusive and wicked
- He had no remorse (forcing Patrick to trick the sick girl at the carnival)
- Him & RJ have both been called 'showmen'
- Him & Patrick had a falling out - From there, Patrick ran off with his wife, and maybe that lead Alex to kill Patrick's wife and child (since that sort of murder is pretty personal).