investigation. so far former officer dean hasm. lester now to the impeachment inquiry in washington and testimony today from a key witness on the trump administration's dealings with ukraine. we get more from nbc's kristen welker. >> reporter: tonight, the president's former top russia advisor delivering critical testimony on capitol hill, a person familiar with the matter telling nbc news fiona hill planned to tell lawmakers that the president's outside lawyer rudy giuliani sidestepped official channels to run a shadow foreign policy in ukraine. giuliani denied that allegation to nbc news today. chairman of the house intelligence committee ada>> gdh appearance is also stoking fear among people close to the president thursd a source familiar with his sondland plans to c that when he told the top diplomat in ukraine there was no quid pro quo, he was relying solely on what president trump