In the last episode of the season "Blue bird" the team investigate a cold case, maybe this cold case is about the "car crash" which lead to Bret Stiles taking over visualize, as from my memory that is the only such unsolved case that has been mentioned in the show, this could then lead to information about Red John confirming or disproving that he was Thomas, as Red John is known to have a visualize connection. Tell me what you think guys!