From the October 31 edition of Fox News' Tucker Carlson Tonight:

TUCKER CARLSON (HOST): Who exactly is this whistleblower who apparently started it all? We still don’t know the answers to those, the most basic questions.

Last night the site Real Clear Investigations published an article about the man it says is the whistleblower. As of tonight, Schiff’s office has not denied the substance of that piece, publicly available information corroborates some of the details in it.

It’s a remarkable story, in any case. The man is a registered Democrat who worked on the National Security Council as a holdover from the Obama administration. Over the years he worked for both Joe Biden and disgraced CIA director John Brennan.

A news article from 2017 identifies this same man as pro-Ukraine and anti-Russia. It says that he was the subject of bitter complaints from some Republicans who knew him. In other words, more than two years ago conservatives were publicly charging that this man was working from inside the building to undermine the Trump administration.

According to the Real Clear Investigations piece last night, they were right. The man worked with processional left-wing activists, the piece says, to attack Donald Trump. He also held meetings with Adam Schiff’s staff members, several of whom were his former colleagues from the Obama White House.

And tonight, we can tell you it seems likely that this man, the man in question, was also a source for Robert Mueller’s investigation, his Russia investigation. What appears to be the man’s name can be found in a footnote in the final report.