After a closed-door Senate meeting on Thursday, Republican Sen. Lindsey Graham said that the federal investigation of the alleged collusion between Russia and the Trump campaign s now a criminal investigation.

“It was a counterintelligence investigation before now. It seems to me now to be considered a criminal investigation,” Graham said after talking with Deputy Attorney General Rod Rosenstein.

“What does that mean for the Congress? I find it hard to subpoena records of somebody like Flynn who may be subject to a criminal investigation because he has a right not to incriminate himself,” Graham added. “As to Comey, the former director of the FBI coming before the committee, if I were Mueller I would jealously guard the witness pool.”

Graham said that special counsel Robert Mueller was looking at the investigation as a criminal matter.