He has a potential motive to lie or to distort the truth. Or maybe he has not, but an outside observer cannot know it for sure. So if he will speak freely he wi

He has a potential motive to lie or to distort the truth. Or maybe he has not, but an outside observer cannot know it for sure. So if he will speak freely he will become a target of attacks based on his supposed hidden motivation, and it can happen without regard to his real impartiality.