Firstly let me start with telling i am not sure who RED JOHN is ... But i want to share that four out of seven suspects contacted each other at some point of time in a situation relating to RED JOHN.

Proof :- In s05e08 Bob Kirkland in talking to Thomas McAllister on phone about bringing CBI instead of marshals for the barn case.


In s06e02 Bertam,Smith and Tom again have a meeting. So one might conclude that all these three people are not intimidating enough to be Red john.

Now left with haffner ,Stiles,Partridge,Bob

Haffner has been fooled by Jane and he seems to be more of a laborer for visualise.

left with Stiles , Partridge ,Bob

Stiles is too old to be called a kid 25 yrs ago.so leaves us with partridge and Bob.

now considering Partridge is dead .BOB KIRKLAND has all the qualities to be Red John ,He is authoritative ,intimidating and his mannerisms are weird , looks like he is concerned about keeping things in in place like most of serial killers.

So my bet would be BOB KIRKLAND !!!!!!!