The U.S. Office of Special Counsel alerted the FBI today to allegations that women have been offered cash to fabricate sexual assault accusations against Robert Mueller.

In a rare statement, Mueller’s top spokesman Peter Carr said Mueller’s team learned of the alleged payoff scheme last week.

“We immediately referred the matter to the FBI for investigation,” Carr said, calling the claims against Mueller “false.”

The FBI declined to comment.

A U.S. official familiar with the matter confirmed to the New York Daily News that the special counsel’s office was alerted to the purported scheme by reporters who had inquired about receiving emails from a Florida woman who alleged that right-wing conspiracy theorist Jack Burkman had offered her more than $20,000 to accuse Mueller of sexual misconduct.

The email, which was screen-grabbed and posted on social media by several journalists, states someone named Bill Christensen recently called the woman and asked questions about Mueller, whom she said she worked for as a paralegal at the San Francisco offices of law firm Pillsbury, Winthrop, Shaw & Pittman in 1974.

Christensen told the woman he represented Burkman, who is a registered GOP lobbyist and infamous for perpetuating a debunked conspiracy theory that Hillary Clinton was responsible for the 2016 death of Democratic National Committee staffer Seth Rich.

“He then offered to pay off all of my credit card debt, plus bring me a check for $20,000 if I would do one thing,” the woman said.

She said Christensen was reluctant to explain over the phone and urged her to download Signal, a secure messaging app.

“I downloaded the app and he called me on that app a few minutes later,” the woman said. “He said (and I will never forget exactly what it was) ‘I want you to make accusations of sexual misconduct and workplace harassment against Robert Mueller, and I want you to sign a sworn affidavit to that effect.’”

The woman says she “immediately” hung up and deleted the app.

“I didn’t see Robert Mueller very much when I worked at Pillsbury, but when I did see him, he was always very polite to me, and was never inappropriate,” she said. “I don’t know what these people are looking for but I’m not going to be part of some kind of Washington, D.C., drama for any price.”

Mueller worked as an attorney at the San Francisco law firm between 1973 and 1976. A spokesman for the law firm did not return a request for comment.

Within minutes of Carr’s statement, Burkman posted a video on Facebook revealing he plans to host a news conference in Arlington, Va., on Thursday focused on “the first of the sex assault victims of Robert Mueller.

“Mueller is a bad guy, not just because of what he does in the courtroom, but because of what he does outside of the courtroom,” Burkman said. “Mueller has done bad things to a number of women, the first of whom is coming out this Thursday.”