Bob Kirkland:  
   
       - has been following Names investigation from day one
       - has probably shook hands before the one shown during the Volker cases
       -Miranda was killed five years ago(2007) giving enough time to change his face          "Lizard Face" and asking Lennon if he recognized him. 
       -Kirkland stole Names board through his connections with Homeland Defense.
       -Kirkland is on Janes suspect list.(Lisbon mentions to Jane: "make sure you add how creepy he is to the list." In Episode 19)

   I wasn't sure what he was at first, but now I believe he is Red John. I believe this precisely because he is not in either of the last two episodes. 

 I think things would been different had they not been renewed for another season, but Kirkland did not die nor anything happened to him and he is now integral to some closure to the story...so yes Kirkland is Red John. 

The evidence will only get stronger as time goes by...