(CNN) The Columbia University Law School professor and confidant of former FBI Director James Comey refuted a charge by President Donald Trump and his advocates in the media Monday: that Comey shared classified information with journalists.

Daniel Richman, with whom Comey shared at least one memo -- the contents of which Richman shared with New York Times reporter Michael Schmidt -- said President Trump was simply wrong.

"No memo was given to me that was marked 'classified,'" Daniel Richman told CNN. "No memo was passed on to the Times."

Richman did share the contents of one memo, he said, but "the substance of the memo passed on to the Times was not marked classified and to my knowledge remains unclassified."

During Senate testimony in June, in which he said he gave memos to someone he described as a Columbia University professor, Comey said he specifically wrote the memos to avoid including classified information.

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