Former Attorney General William Barr says Trump got "madder and madder" when challenged on unfounded allegations of election fraud

When former President Donald Trump summoned then U.S. Attorney General William Barr in early December, he says he knew it wasn't going to be a pleasant meeting and thought Trump was going to fire him. 

"I told my assistant as I left the office she may have to pack up for me because often he would tell you not to come back," Barr told "CBS Mornings." 

When he entered the Oval Office, Barr said the conversation quickly turned into a back and forth between Barr and Trump about the former president's allegations of widespread fraud.