I believe RJ is Bob Kirkland
based off of these ideas; he broke into Jane’s office, Occam's razor which is
bought up in the episodes (discreetly and mentioned in a few) suggest that it
is him based off of its principle the hypothesis with the fewest assumptions should be selected (the simplest
answer should be chosen), killed Lennon in the hospital after asking if he recognizes him (kind of
puts it you off the idea of it being him because it’s not his style, but if you
think back Red john has killed and messed up before because of an event that
happened that was unplanned for) knew that Jane was in the mental asylum and
could have gotten hold of all his therapy sessions (possibly even the therapist
herself which seems less likely) which would have informed him of the happy
memory. Even with this evidence there is still no definitive proof that it was
him and I am open to all suggestions (unless someone says Patrick that is just
a stupid comment and should not even be said it’s not on the list and Heller
said its someone on the list therefore not Patrick)