The end of series 3 the only person who could have set up the fake John encounter in the Mall would have been Bertram.

Apart from Stiles & Bertram it is hard to see any of the other suspects having the charisma to manipulate their acolytes. Both are also follicly challenged making it easier for Hawker to confirm that Carter was not Red John.

If the producers have carried this through and not just made the suspects up  at the end of this series Bertram's build bothers me being larger than the figure that recited Tyger to the captive Jane and passed Rebecca in the corridor - unless he always gets his acolytes to do the work.