Whoever Red John is, my theory is that he is someone from Patrick Jane's past in the circus. They may have met before (and Lorelei's words about shaking hands may refer to some distant past), but for some reason Patrick doesn't recognize him (RJ was a child/a teenager or perhaps in disguise?). That would explain how he knows about Patrick's happy memory. Bruno Heller says in his latest interview that this question is going to be answered in the next episode - I'm really looking forward to it.
