The FBI has been asked to look into claims that women were offered money to fabricate sexual assault allegations against Mueller. The special counsel is leading the investigation whether the Trump presidential campaign colluded with Russia.
Special Counsel Robert Mueller's team has asked the FBI to look into claims that women were offered money to fabricate sexual assault allegations against Mueller, who leads the probe into Russia's attempts to influence the US election in 2016.
"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," Peter Carr, a spokesman for Mueller, said on Tuesday.
The Federal Bureau of Investigation declined to comment.
Jack Burkman, a lawyer and Republican operative who has in the past promoted right-wing conspiracies on social media, told Reuters he was speaking to five women who claimed they were sexually assaulted by Mueller, and denied paying them for the information.
He said he would have a news conference close to Washington on Thursday with one of the women who claimed she was sexually assaulted by Mueller in 2010, and that the other four women still needed to be vetted.
Jennifer Taub, a professor at Vermont Law School, said she received an email on October 22 from an individual offering to compensate her if she would discuss her "past encounters" with Mueller, who she says she has never met.
Taub said she found the email, a copy of which was seen by Reuters, to be "creepy" and forwarded it to Mueller's office. The email was sent to her by a person who claimed to be a researcher at Surefire Intelligence, Ltd.
Reuters was unable to connect with anyone at phone numbers listed on Surefire Intelligence's website.
Burkman declined to say if he was working with Surefire.
Mueller is leading the politically sensitive investigation into Russian meddling and possible collusion between Republican Donald Trump's 2016 campaign team and Russian officials.
Burkman has been critical of the Mueller probe and sought to raise funds for Rick Gates and Michael Flynn, two former Trump aides who pleaded guilty to charges brought against them by Mueller's team.
Trump denies any collusion and has repeatedly described Mueller's probe as a partisan "witch hunt."
Russia denies the allegations that it interfered in the election.