Washington (CNN) Aides to President Donald Trump questioned him during the 2016 campaign about the existence of an audio tape in which he purportedly said the N-word, a racial epithet, during production of his reality TV show "The Apprentice."

But officials' divergent accounts, shifting stories, and an overall dearth of credibility have combined to create little clarity on the circumstances surrounding those conversations.

Corroboration of the campaign's concern over the tape -- whose existence has yet to be verified --brought the controversy surrounding former Trump aide Omarosa Manigault Newman's new book into another day, even as Trump and his aides sought to discredit and attack her character.

Lynne Patton, a Trump campaign aide and assistant to one of the President's sons, told fellow campaign officials on a call in October 2016 that she confronted Trump about the existence of the tape and that he denied it, according to a recording of the call publicly released Tuesday morning by Manigault Newman on CBS

"I said, 'Well, sir, can you think of anytime this might have happened?' and he said no," Patton said on the call with Manigault Newman, Katrina Pierson, a Trump campaign spokeswoman, and Jason Miller, the campaign's communications director, according to the audio released Tuesday.

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