Sen. Chris Murphy (D-CT) raised alarm over Rudy Giuliani’s actions on behalf of President Trump in Ukraine on Friday evening and called for an investigation.

Murphy wrote to the Republican chairman of the Senate Foreign Relations Committee, which he sits on, and said he was “alarmed” and “deeply concerned” by Giuliani’s intentions. Giuliani later canceled his trip to the Ukraine where he planned to ask the new government to launch investigations into issue that would be politically useful to Trump — like how the Russia probe “really” began and former Vice President Joe Biden’s son.

“I am deeply concerned about the implications of this for United States foreign policy. Specifically, Rudolph Giuliani, the President’s personal lawyer, has apparently held meetings with Ukrainian officials in the United States and plans to travel to Ukraine for further discussions,” Murphy wrote in the letter addressed to Sen. Jim Risch (R-ID), obtained by NBC News. “As far as we know, none of these meetings are being coordinated with the U.S. State Department or other government agencies.”