I don't think it was a matter of credibility, Eva. He provided what testimony he was encouraged/directed to give. He certainly asked enough questions and kept his eyes and ears open in the short time he was backstage at Ford's. To me, he is/was not credible, but he was able to twist/magnify what few things he picked up to provide testimony that made Ned Spangler look pretty guilty to those who needed someone to be held accountable.