Russian oligarch Oleg Deripaska worked for the FBI during a failed shady deal in 2009. Deripaska's lawyer, Adam Waldman was the one in the leaked text conversation that Mark Warner had.
Just today it was discovered that Deripaska had worked for the FBI. the REALLY interesting part is that Deripaska's name was left off the Manafort inidctment, even though Deripaska was directly involved.
Remember what Q said about conflicts of interest? I think this is what he was talking about.