The special counsel Robert Mueller's office has referred to the FBI an alleged scheme to pay women to falsely accuse Mueller of sexual misconduct.

The scheme came to light when several journalists covering the Russia investigation revealed that they'd been contacted by a woman who said she was offered a five-figure payment to say the special counsel sexually harassed her.

In a copy of the woman's email obtained by Business Insider, she wrote that she was contacted by a man with a British accent working for a GOP lobbyist, Jack Burkman, who said he would pay her $20,000 to accuse Mueller of workplace sexual harassment and sign a sworn affidavit to that effect.

Burkman said he does not know the woman, and reporters cautioned that the woman proved to be "unreliable" and was unwilling to further discuss her claims over the phone.

But Burkman said on Tuesday that he "will reveal the first of Special Counsel Robert Mueller's sex assault victims" on Thursday.

The special counsel Robert Mueller's office has referred an alleged scheme to the FBI for investigation in which a political operative offered to pay women to falsely accuse Mueller of sexual misconduct and workplace harassment, a spokesman for his office told Business Insider.

"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," the spokesman, Peter Carr, said in a statement.

The lobbyist at the center of the alleged scheme, Jack Burkman, claimed that on Thursday he "will reveal the first of Special Counsel Robert Mueller's sex assault victims."

Scott Stedman, a freelance reporter who has closely tracked the Mueller probe, first publicly divulged details about Burkman's alleged offer late Monday night.

"Based on information that I am privy to, I believe false accusations will be spread about Mueller in order to discredit him and possibly the journalists who are preparing this story," he tweeted.

Stedman said he was contacted earlier this month by a woman claiming to be Mueller's former colleague who said she got a phone call from a man working on behalf of a GOP operative offering women money to make sexual assault allegations against Mueller.

He added that the woman turned out to be "unreliable" and that the operative was also "extremely willing" to confirm that he had paid women to come forward with false claims about the special counsel.

Marcy Wheeler, an independent journalist who gained recognition for her coverage of the Scooter Libby trial in the 2000s, said she'd had a similar experience.

How Mueller's office first learned of the scheme

Mueller's office first learned of the scheme when a woman got in touch with them and said she herself had been offered money to make false claims of sexual harassment against the special counsel.

The special counsel's office was also contacted by several reporters who were told about the alleged scheme by a woman who said a man working for the agency Surefire Intelligence and Burkman offered her around $20,000 "to make accusations of sexual misconduct and workplace harassment against Robert Mueller," according to a copy of the email obtained by Business Insider.

Robert Mueller. Aaron Bernstein/Reuters

It's unclear whether the woman's story is entirely factual. Stedman wrote that after she contacted him, "she wouldn't get on the phone" to discuss her claims and "lied about journalists she was working with."

The woman said in her initial email that she was contacted by a man with a British accent who said he worked for Burkman and wanted to ask her a few questions about her time working with Mueller when she was a paralegal at the law firm Pillsbury, Madison, and Sutro in 1974. The firm told The Atlantic on Tuesday that it "has no record of this individual working for our firm."

The woman said that when she told the man she had only worked with Mueller for a short while before leaving to take care of her son, the man "then changed his tone, and mentioned that he might be able to help me pay off some debt."

"He knew exactly how much credit card debt I had, right down to the dollar, which sort of freaked me out," she wrote.

The woman said she declined the individual's offer, but that he contacted her again two days later.

"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," she wrote, adding that when she asked him what he wanted her to do, he told her they could not talk about it on the phone and that she should download the encrypted messaging app Signal.

When he called her on the app a few minutes later, the woman wrote, he told her, "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 said that she immediately hung up on the man 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 wrote.

Burkman said he does not know the woman who emailed reporters about the alleged scheme.

Later Tuesday, The Atlantic reported that a second woman was contacted by someone working for Surefire Intelligence who claimed to be investigating Mueller.

The woman, Jennifer Taub, is an associate professor at Vermont Law School and a CNN commentator. A man using a Surefire Intelligence email address reportedly got in touch with Taub and said he would compensate her "at whatever rate you see fit" in exchange for information about her "past encounters" with Mueller. Taub told The Atlantic she has never had any interactions with the special counsel.

Several journalists on Tuesday said that Jacob Wohl, a far-right conspiracy theorist and disgraced former hedge funder, was involved in Burkman's and Surefire Intelligence's alleged scheme.

When contacted by NBC News, Wohl said he didn't have any role in the matter.

But the outlet reported that Wohl's email address is the one listed in the domain records for the firm's website. Calls to a number on the website also reportedly went to a voice mailbox belonging to Wohl's mother.

On Tuesday evening, Stedman tweeted that he visited the address listed on Surefire Intelligence's website in Irvine, California.

"A representative of the office tells me they have nothing to do with the company and have no information about it," he wrote. The representative added that "we have absolutely nothing to do with that company."