>> reporter: trump jr. testified he never told his father about the meeting. when asked, did you inform your father about the meeting or prior to the meeting? trump jr. responded, no, i was not. when he was later asked why he didn't share news? i wouldn't tell him anything until i knew what was myself. last year he testified before two congressional meetings. a source familiar tells cnn, he did not testify trump had any advance only in of the meeting. now his attorney rudy guiliani is attacking the credible. >> man is a liar a proven liar. there is no way you will bring down the president of the united states on the testimony uncorroborated of a proven liar. i germany tee you, this guy is a proven liar. >> reporter: when just a few weeks ago, guiliani seemed to have plenty of faith in con's truthfulness. >> if he believes it's in his