I’m not accusing anyone of being Red John, but there are
some interesting points I haven’t seen being mentioned anywhere:

In the last episode of season three,” Strawberries and Cream”,
minute 32, when LaRoche arrives to take Gupta, he addresses Lisbon and Jane and
says well done to them. But just note the tone of his voice and that he is actually
staring at Gupta in a very meaningful manner when he utters those words, as if
he was addressing him, sarcastically of course, to which Gupta responds also
meaningfully, as if being rebuked because of his lack of success. LaRoche then asks
if he has given them anything to which Jane responds “Not a thing.”, and less
than a minute later Gupta is killed by LaRoche. So what do you think about that?
Is it a real clue to LaRoche being in contact with Red John or even Visualize
for that matter? Or is it another red herring thing?

And a little and probably farfetched hunch about Father
Debuono in the last episode, “Red Barn”. I suspect him of being in contact with
Red John or at least knowing his identity, because he revisited the farm at the
time in which Red John supposedly worked there, his time with Visualize was an
early stage in a long spiritual journey, seemed not to be telling the truth
about not being aware of the symbolic meaning of the smiley face drawing on the
wall of the barn, which seemed strange to Jane as well, and to explain his
ignorance mentioned that he was a missionary in central America, which
increases the possibility of him crossing Mexico, and I don’t know how exactly but
makes me suspect him as a possible candidate for the person who killed Jarred
Renfrew and the hooker, because the smiley face drawn on the wall of the
bathroom was not the first thing a person entering that room would see, but the
first thing we saw, maybe to mislead us.

What do you think?

In the pilot episode why did they focus on the paramedics forearm tattoo? In Red John's Friends it's obvious the girl wrote the message (blood on hands, facing the wall) and she was mexican so maybe her english wasn't very good. Could she have been trying to describe her killer as "He is marked"? 

I do like Walter Mashburn for Red John though.

Robert "Bob" Kirkland 

He ask for information on the red john's when they show jane's introduction into  the cbi.
he shakes jane's hand, and when janes asked "do i know you?", he simply replies "no, but i know you."