In the beginning there were seven. Brett Partridge, Bret Stiles, Bob Kirkland, Reede Smith, Gale Bertram, Thomas McAllister and Ray Haffner.  In the first four episodes Brett Partridge and Bob Kirkland have been killed and eliminated. Leaving us with five suspects. 
In my opinion there is only man can be Red John and that is Raymond Haffner. I will explain why:
   First lets talk about the other four remaining suspects. 
Gale Bertram, Tom McAllister and Reede Smith are obviously members of this "Tyger, Tyger organization". Reede Smith as we saw is pretty much the "Hitman" of the group. Gale Bertram started and is the leader of the group. Tom McCallister is Bertram's right hand man and is used to keep an eye on Jane. Brett Partridge was the crime scene stager and clean up guy. I also believe that CBI Ron is part of this group. None of these men are Red John.     Bret Stiles isnt Red John either. He met Haffner when he was a troubled teen and took him in. Because of Bret Stiles Ray Haffner joined "Visualize" where he learned all of his techniques and skills. Brett Stiles was accused of killing Timothy Farragut during the early years of "Visualize". I believe Haffner has evidence proving Stiles committed the murder but came to an agreement with Stiles. Thats why Stiles wont reveal Red John's identity and protects him. 
 Before joining the CBI Ray Haffner was an FBI agent in the Organized Crime Division and is an expert in  . With those tools at his disposal Haffner likely found out about the secret "Tyger, Tyger" Organization. He then in Season 2 finale as Red John saves Patrick and recited that famous poem. " “Tyger, tyger, burning bright, in the forests of the night, What immortal hand or eye could frame thy fearful symmetry?”  It was simply a friendly warning to Jane to watch his back. He also says "RollTide". Hmmm...It just so happens that ray Haffner is a former football player.      Ray Haffner shows up in season 4 as the new supervising agent at CBI and Jane's boss. What better way to keep an eye on your biggest adversary and see exactly what you are up against. They even shook hands on screen.  People say Patrick played and outsmarted him when it was Haffner who was playing Patrick all along. Remember Haffner asking Cho if Patrick was smarter then him. Odd right?       Haffner leaves the CBI and starts his own private security agency.That along with his wiretaps and creative surveillance techniques is how he was able to figure out Jane's list of seven suspects. Haffner was also the person closest to the house where Partridge was killed and Lisbon Kidnapped. Instead of killing Lisbon Haffner draws a different smiley on Lisbon's face and even brushes her lips. Remember Haffner either has a thing for Lisbon or is in love with her.       Lastly Red John is a narcissist and master manipulator. Haffner always dresses nice and cares about his appearance. No other character was shown working out. Coincidence? Then we have the nurse coming into Lisbon's room looking for Camen Lee. Haffner was the only suspect to visit Lisbon in the hospital. I think he sent the nurse in first to see if Patrick was with her so that he could avoid Patrick, see Lisbon and Make sure Lisbon didnt know his true identity as RED JOHN.