Not a theory but a statement from B. Heller.

"There is a clue buried in that final sequence that will pay off big time in the finale of the Red John story. A very big clue. No one will get it from the clue as it is laid out in the episode, but it will pay off later."

It's certainly a problem for these first few episodes. How do you
confront these people when they know what you know, but you don't know
which one of these seven people is your man? They very much have to get
into each one of these suspects' business and to look and them and to
investigate them and to spend time with them. So, it's a game of cat and
mouse. It's not clear who's the cat and who's the mouse."

- BRUNO HELLER



Who's who then?