The special counsel's office has asked the FBI to investigate allegations that women have been offered money to make up false claims about Robert Mueller.

“When we learned last week of allegations that women were offered money to make false claims about the Special Counsel, we immediately referred the matter to the FBI for investigation,” special counsel spokesman Peter Carr wrote to VICE News in an email.

The special counsel's office learned of the allegations from reporters who said they'd received outreach about the story in recent days, Carr said. The rare public statement from the special counsel, which normally maintains a stony silence, suggests the alleged plot is being taken highly seriously.

Several journalists reported Tuesday that they’d received an email roughly two weeks ago from a woman who claimed she'd been offered money from “some sort of politics guy” whom she identified as Jack Burkman to invent accusations of sexual misconduct by Mueller. As if on cue, Burkman, a Republican lobbyist and radio host, announced on social media Tuesday that he plans to bring forward a “client” to make claims of sexual assault against Mueller on Thursday.

In the email, which was detailed by a number of reporters, including the Atlantic’s Natasha Bertrand and independent journalists Yashar Ali and Scott Stedman, the woman claimed she had been approached by a man who knew she had worked with Mueller at a private law firm in the 1970s and offered to pay her money to make false claims about his conduct there.

In the email, the woman claims that Burkman, through an intermediary, offered to pay off the exact amount of her credit card debt, plus up to $30,000 in bonuses, in exchange for making the allegations. The woman said she declined the offer and closed the email by noting that Mueller was “always very polite to me, and was never inappropriate.”

According to journalist Ali, the email was sent 13 days ago, but it stayed largely private until late Monday night, when Trump supporter Jacob Wohl tweeted that he had been told by “several media sources” that a scandalous article about Mueller was breaking soon. In a series of tweets, Stedman warned any looming story was likely a hoax and detailed his attempts to confirm the woman’s claim. Stedman also wrote that Wohl said his information came from a GOP lobbyist.

On Tuesday, Burkman posted a video of himself on Facebook saying he plans to bring forward a woman on Thursday. The event will take place in at the Holiday Inn in Arlington, Virginia, Burkman said.

Burkman said the woman would “unveil a very bad sexual assault.” And he claimed she would be just “the first of the sex assault victims of Robert Mueller.” In a statement posted on Twitter, Burkman denied offering anyone money.

“The allegations of paying a woman are false,” Burkman wrote.

Burkman is no stranger to right-wing conspiracy theories — he once launched his own private investigation into the death of Democratic staffer Seth Rich. Last year, he called reporters to the same Holiday Inn in Arlington on the promise of revealing claims of harassment against a sitting member of Congress. But in that case, according to an account of the event in The Washingtonian, his client never showed up.