Red John must be part of the Tyger, Tyger group and tied with Visualize. The only suspect left that fits the age, physical description, and could be part of both groups is Haffner. I think members of the Tyger, Tyger group suspects that Red John is one of them, but none of them are sure who. The groups illegal activities prevents them from their own internal investigation into the identity of Red John. Bertram's interest in Jane's investigation is to keep the capture of Red John from bringing down the group. Red John being part of the group, and smarter than the rest of the group, he would have info to take them down.They want Jane to do what they cannot, reveal Red John, so Tyger, Tyger can kill him.