Veteran reporter Bob Woodward said Friday that he conducted a thorough investigation into possible Trump-Russia collusion while researching his latest book, “Fear: Trump in the White House,” but found no evidence of a conspiracy.

“Did you Bob Woodward hear anything in your research or your interviews that sounded like espionage or collusion?” conservative radio host Hugh Hewitt asked Woodward during an interview.

“I did not. Of course I looked for it, looked for it hard,” replied Woodward.

Woodward, who is best known for his investigative work uncovering the Watergate scandal, did leave open the possibility that special counsel Robert Mueller has secret evidence that President Donald Trump or his campaign worked with the Kremlin to influence the 2016 election.

“We’re going to see what Mueller has,” Woodward said.

“[Former Trump attorney John Dowd] may be right. He has something that Dowd and the president don’t know about — a secret witness, or somebody who has changed their testimony. As you know, that often happens and that can break open or turn a case,” the reporter continued.

“But you’ve seen no collusion?” Hewitt asked.

“I have not,” said Woodward.

Dowd, a veteran white collar attorney, served as Trump’s personal attorney for the Mueller investigation from June 2017 to March. As part of that job, he helped provide 1.4 million campaign documents and 37 witnesses to Mueller’s team, Woodward reported. (RELATED: Trump Comes Out Swinging At Bob Woodward)

Dowd is quoted extensively throughout the book saying that there was no evidence of collusion. Toward the end of his tenure, Dowd became worried that Mueller had taken advantage of his cooperation with the investigation. Dowd, who adamantly opposed Trump testifying to Mueller, left open the possibility that the special counsel had a secret piece of evidence he did not know about.

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