This show has one big, big flaw.

Why isn't CBI using fingerprints and DNA to bind suspects to crime? That way they would already know who was Red John, I mean he's probably left alot of biological markers at his murder scenes and leftover cup of tea.

I know why, to get the narrative feeling right - this is a 19th century show in modern setting - it isn't realistic at all. That's why all these theories a bit over the top. The show itself is very basic and simplistic so stop trying to overanalyze everything. 

I doubt the writers will prove they have Sherlock Holmes mind, rather something dull like McAllister or Partridge (brrrrrrroring)