I was watching all the episodes from season 1 episode 1 to season 7 episode 3 and I realised something odd about Wain Rijsbi. From the very start, I knew it was him because he is just like Red Jon; he is smart, tall and works in the FBI. In season 4 episode 27 (entitled "Red Rose"), Petrick says that Red John is in the FBI...so is Rijsbi!!! Plus, Ven Peelt, whom recently divorced Rijsbi also told Petrick that Rijsbi was Red Jon.
From the evidence above, it is now evident Wain is Red Jon.