>> he had some very specific instruction for me. i had to go to the lawyers, to john eisenburg, senior counsel for the national security council, to basically say tell ieisenburg, ambassador bolton told me, "that i am not part of this, whatever drug deal that mulvaney and sondland are cooking up." >> reporter: republicans tried to attack hill's credibility. >> dr. hill, you have provided me probably the greatest piece of evidence that's before us to illustrate the problem with hearsay. >> reporter: but hill pushed back. >> we're here just to provide what we know and what we've heard. i understand that for many members this may be hearsay. i talk about things i heard with my own ears. >> reporter: also testifying, david holmes, an american diplomat in ukraine who says he heard the president's words himself. holmes was sitting with sondland in an outdoor restaurant in kiev when sondland picked up his cell phone and called the president. >> this was an unsecure cell phone, is that right? >> yes, sir. >> in the middle of a restaurant in kiev?