Updated at 4:53 p.m. ET
The office of Justice Department special counsel Robert Mueller has notified the FBI about an alleged scheme in which a woman was offered payment to make false sexual misconduct charges against Mueller.
A spokesman for Mueller confirmed the referral on Tuesday in a statement.
News organizations including NPR have received information about claims related to the alleged scheme. Reporters have so far not been able to verify them.
When the special counsel's office became aware of them last week, it alerted the FBI, said spokesman Peter Carr.
The FBI declined to comment.
The alleged scheme
An account of the alleged scheme appeared unsolicited in the inboxes of a number of reporters around Washington, D.C., in mid-October in an email sent from a Gmail address.
The email received by NPR appears similar to other copies that were posted by journalists on Tuesday.
In the email, a person identifying herself as a woman from Florida describes having been contacted out of the blue by someone with detailed knowledge about her work history and her personal finances.
That person, according to the account, asks her to establish contact over an encrypted messaging application and then, in exchange for tens of thousands of dollars, to make false but potentially politically damaging misconduct claims against Mueller.
NPR attempted several times to make contact with the person to substantiate her story and received two follow-up messages from the account.
One of the responses included a description of another phone call from a stranger in furtherance of the original offer. The other message declined a phone conversation about the story, citing the need to preserve a written record of the exchanges.
The purported announcement
Carr's statement about the referral on Tuesday preceded a putative news conference that may have been scheduled for later this week at a hotel just outside Washington.
Conservative media personality and lobbyist Jack Burkman, who was referenced in the unsolicited email from the alleged Florida woman, said on Twitter that he planned to convene the news conference to announce sexual misconduct allegations against Mueller.
Burkman later posted an update that said the allegations about payment to a woman were false.
Burkman has moved on the periphery of the Russia imbroglio for months. He reportedly bankrolled an investigation into the death of a Democratic National Committee aide who was the subject of a conspiracy theory related to one thread in the Russia investigation — a theory since debunked and retracted by some of its supporters.
Burkman also reportedly was attacked by a man he hired to conduct that investigation, as The Washington Post reported. And before that he offered monetary rewards for information about earlier phases of the story and helped raise money for Donald Trump's former campaign vice chairman, Rick Gates.
Gates has since pleaded guilty to federal charges and has cooperated with investigators, including in last summer's trial of Trump's former campaign chairman, Paul Manafort.
Burkman has a show on NewsMax TV, which is run by Christopher Ruddy, a friend and supporter of Trump.
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