For me, CBI Ron is red john or his right hand man
cmonn guys, he is always in the background his real name is John Troy Donovan!!!!
many scenes in the series made him guilty, the first time he was seen in the series was in "seeing red"!! , he doesn't speak alot, he wears the same ring as red john, he has been seen walking with many red john disciples, heez got the body for it, when he appears, the red john weird sound go on. If he is not red john, then iam 90% sure he is his right hand man.