Well.. I belive in Heller when he said "Red John is dead", so.. is it in my head "Maybe I just not understand" So, that is my theory: the serial killer Red John, can't appear anymore. "The Blake Association" was who covered their tracks. Now, without "The Blake Association", he could not be the serial killer named "Red John", because he would be catch. Now, is not more a murder by "Red John", is the guy behind "the mask" playing with Jane. Jane killed Red John, and Red John was always a mask. Now, we'll meet the men behind..
In my head again, Brett Partridge or Ray Haffner.
Jane aways says: Trust your instincts, Lisbon.. (or "Elementary, my dear Watson" Hahaha.. Just a joke ;) but..
Maybe was the writings saying to us..
Trust your instincts..