Guys, you might think this is just another stupid theory, but I am not lying.

Red John is one of 2 people: Reede Smith ( http://thementalist.wikia.com/wiki/Reede_Smith ) or Gale Bertram ( http://thementalist.wikia.com/wiki/Gale_Bertram ) . I figured this out by going on their pages (above) . It shows the last appearance (episode) . The other 3 suspects' (Bret Stiles, Sheriff Thomas McCallister, Ray Haffner) Last Appearance is the episode "Fire and Brimstone". My two suspects' last episode says "Red John". That's what I think, but out of those two: Reede Smith sure has the antagonistic attitude, but Gale Bertram sure has the recourses. I'd say Gale Bertram, that's it.