A fresh allegation of historical sexual assault has been made against black cab rapist John Worboys, it is understood.
The non-recent sexual assault, which was reported to police this month, is reported to have taken place in 1997.
The Metropolitan Police are now investigating the claim, and would make no further comment on the ongoing investigation.
No arrests have been made.
Sixty-year-old black cab driver Worboys was jailed indefinitely in 2009, with a minimum term of eight years, for drugging and sexually assaulting women passengers.
He was convicted of 19 offences relating to 12 victims but is suspected to have been linked to 102 complaints in total.
A controversial Parole Board decision to approve his release later this month, following his minimum eight-year term, has led to a moral outcry.
Meanwhile, MPs have expressed fresh anger against his release, after it emerged Warboys had been moved to a Greater London prison.
Worboys was reportedly transferred from HMP Wakefield in West Yorkshire to HMP Belmarsh in south-east London over the weekend.
Justice Secretary David Gauke is facing demands for Worboys to be kept out of the capital – the area in which he preyed on his victims.
Tory MP Zac Goldsmith told the minister that Worboys’ proposed release “has absolutely horrified and terrified his many, many victims”.
Labour MP Neil Coyle told the House of Commons that Worboys “is not welcome back” to his home in Rotherhithe, south London, in the MP’s constituency.
“He has not served the sentence he was given and was not prosecuted for the vast majority of his crimes,” he said.
Mr Gauke said he had stressed to officials “the need to ensure that the concerns of victims are at the heart of the process” in deciding Worboys’ licence conditions.
He also pressed the need for the “most stringent” conditions to be placed on Worboys’ release.
Last week, Mr Gauke revealed the Government will not be seeking a judicial review of the decision to release Worboys.
Commenting on reports of Worboys’ prison transfer, Richard Scorer, a lawyer at Slater and Gordon, which represented a number of his victims, said: “This is extremely distressing for our clients as yet again they have not been informed about developments in the Worboys case.
“It is an insult that they have had to find out from the media of every new development in this case and it is crucial that they are kept updated.”
The Ministry of Justice said they do not comment on individual cases.