My thoughts are that Red John is not one individual but possibly a couple high powered ppl, eg Gale Bertram and Bob Kirkland, or even the whole Poker playing Club , excluding Teressa?? And that is why there is never a trace of RJ because it is not one person, it could have started off as one person( started on the Farm in the Barn) , but RJ is now more of a collective than an individual. Defintily Bob Kirkland has something to do with RJ