Someone has engaged in an organized effort to smear the reputation and credibility of Jane Mayer, a prize-winning journalist at The New Yorker, according to a New York Post reporter's published accounts and his subsequent statements to Media Matters.

Last week, the New York Post's Keith Kelly reported that The Daily Caller, a right-wing news site run by Tucker Carlson, had spent “several weeks” pursuing false allegations that Mayer had committed plagiarism in at least two articles. One of the allegations involved Mayer's landmark expose about Charles and David Koch -- billionaire brothers who have funded conservative organizations tied to the Tea Party movement.

Kelly tells Media Matters that the plagiarism charges were also pitched to the Post, apparently by a different source than the one that tipped off the Daily Caller. The Post investigated and ultimately reported that the allegations were untrue.

After first saying that the plagiarism story would result in an “extensive piece,” The Daily Caller ultimately told both Kelly and The New Yorker that the article had been spiked.

Kelly has reported that “the person or persons behind the allegations remains a shadowy mystery,” and both Carlson and Daily Caller reporter Jonathan Strong have declined to identify the original source of the smear.

The Daily Caller has significant ties to the Koch brothers and to the business they run: Koch Industries.

Foster Friess, a billionaire Republican donor who reportedly put up $3 million to help launch The Daily Caller, participated last summer in a secret strategy meeting in Aspen intended to help the conservative movement combat the “threats” posed by the Obama administration. The event, which included a lecture by Glenn Beck, was organized by Koch Industries and attended by the Koch brothers.

When questioned by Media Matters, Friess denied any connection to the smear campaign against Mayer and said in an e-mail he “was not aware story was being pursued.”

The New York Post's Kelly noted in a story that Carlson has his own ties to the Kochs:

Carlson is a senior fellow at the Cato Institute, which has strong ties to the Koch brothers although a spokeswoman insisted those ties have diminished lately and that co-founder Charles Koch, who pumped tens of millions into the group over the years, had cut back in 2009 and withdrew funding entirely in 2010. David Koch remains on its board.

The spokeswoman for Cato said she had no direct dealing with the Koch brothers and suggested we call Koch Industries. A spokeswoman for Koch Industries had not answered our e-mailed questions by press time.

Koch Industries has not responded to requests for comment from Media Matters either.

A New Yorker source, meanwhile, told Media Matters that the magazine was contacted by The Daily Caller on January 3 with what the source described as “snippets” of alleged plagiarism by Mayer from pieces she wrote in the past.

Among them, of course, was her article about the Koch Brothers.

The source said some of what was presented by The Daily Caller included instances in which Mayer clearly credited other material that The Daily Caller suggested had been plagiarized.

“We are just happy that they realized there was nothing to it,” The New Yorker source said.

Mayer declined comment.

Kelly first revealed last week in his Post column that The Daily Caller was close to running the inaccurate attack on Mayer's work.

Kelly reported that Carlson told him: “From what I know at this point, it's an extensive piece.” Carlson told Kelly that the story would be posted “sometime later this week.”

But Kelly reported that the next day -- after the piece had been spiked -- Carlson told him: “I have no clue where we got it. I never ask the reporters where they get stuff, only whether it's true. In this case, we didn't have enough.”

Kelly told Media Matters he had been urged to run similar information, but found it to be unsubstantiated.

“Our tip ... was that The Daily Caller was going to do this story,” Kelly said. “It was more of somebody in the know, but it wasn't necessarily the tip passer. It didn't come in directly to me, it came in through channels, it ended up on my desk and I looked into it. The stuff didn't look like it was holding water.”

Kelly said that the Post's source, whom he declined to name, stated: "The Daily Caller has this stuff, maybe they would beat you to the punch."

Daily Caller writer Strong defended the website's pursuit of the story, telling Media Matters: “Checking things out is what a reporter does.”