Red John has short straight hair (as described by Rosalind Harker) so BERTRAM and STILES are out of the picture.
Red John has to have a good physique and strong so Reede Smith is gone.
Now left with Bob , Haffner and McAllister.
According to Dr . Miller Red John is a very good whistler , Out of the three options left in s06e02 they showed Haffner and McAllister whistling just to mess with us. So most likely RJ would be BOB KIRKLAND !!!!!
