Normally I hate CBI Rob theories but I did notice just watching the season 4 final episode that CbI Ron and another agent do show up with Luther Wainright after PJ has supposed to have killed Lisbon and Rigsby. Next time we see old Luther is in the back of RJ's limo. RJ does tell PJ that "oh you had me going a good while" and that "I have a good friend in the FbI, somI found out when they found out" so perhaps CBI Ron is the mole in the CBI. After last season when they went looking for a mole in the CBI we assumed it was Craig O'L. While he was a mole, perhaps he's more connected to the mole RJ has in the FBI and the CBI mole is separate all together.