He and other U.S. journalists said they had received an email from a woman named Lorraine Parsons earlier this month, who claimed someone working for a Republican lobbyist called Jack Burkman had contacted her.
Carr offered no details of the case which may be an effort to discredit Mueller as the investigation continues.
The spokesman, Peter Carr, issued a statement saying that "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".
Around the same time reporters began to be contacted about the assault allegations, Jack Burkman, a Republican lobbyist and radio host began promoting, via his Facebook page, that he is investigating sexual misconduct and alcohol-related allegations against Mueller. I asked him who he was working for, and he told me his boss was some sort of politics guy in Washington named Jack Burkman.
The woman - who has since been unreachable - said that the person who contacted her claimed to work for Burkman, the Hill Reporter said.More news: Betts delivered food to homeless after Game 2 in Boston
The woman claimed she worked briefly with Mueller when she was a paralegal in 1974. The website also has a contact number that redirects to a voicemail that belongs to Wohl's mother. Wohl deleted a theory about the "Deep State scum inside the media", and said the hoax emails came straight from Mueller's office. "It's my understanding that you may have had some past encounters with Robert Mueller", he told Taub, according to the email she forwarded to me on Tuesday afternoon.
The scheme was uncovered after a woman who said she had worked for Mr Mueller years ago told journalists she was offered US$20,000 (S$28,000) to accuse him of sexual misconduct.
Wohl is now claiming his role as "founder" of Surefire Intelligence, which had become the subject of mockery after journalists discovered that the LinkedIn profiles of a number of individuals claiming to be firm employees had profile photos poached from models, actors and stock photo images.
Jacob Wohl describes himself as a conservative, a Zionist and one of President Trump's most loyal supporters. In a statement to the Atlantic, Burkman said the Federal Bureau of Investigation referral was "a joke" and Mueller "wants to deflect attention from his sex assault troubles by attacking me". "When I did see him, he was always very polite to me, and was never inappropriate", she said.
She was busy teaching classes Tuesday when she got a text from Shugerman about The Atlantic story and realized she had her own communication from Surefire Intelligence.