The wife of former Nigerian governor James Ibori is reportedly under arrest in London in connection with ongoing enquiries into money-laundering.
Mr Ibori's assets are said to include a jet and London property
The Metropolitan Police say a woman was arrested at Heathrow airport late on Thursday before a flight to Lagos.
The former Delta State governor is accused of looting state funds.
Mr Ibori's $35m assets outside Nigeria were frozen this year to allow British police time to investigate if they are the proceeds of crime.
A Nigerian news website reports that the 39-year-old Theresa Nkoyo Nakanda Ibori was arrested while waiting to board a Virgin Atlantic flight for Lagos on Thursday evening.
The Met has confirmed to the BBC that officers from the Proceeds of Corruption Unit arrested a 39-year-old woman at Heathrow airport on 1 November in connection with "an ongoing money-laundering enquiry".
The Met says the woman remains in custody at a west London police station. So far she has not been charged with any offence.
Speechly Bircham - the London-based law firm that has been representing James Ibori before the British courts in his efforts to have his assets unfrozen - declined to comment.
James Onafefe Ibori is one of several former Nigerian state governors who remain wanted for questioning in London on money-laundering charges.
The Met's specialist Proceeds of Crime Unit is liaising with Nigeria's Economic and Financial Crimes Commission (EFCC) to find out whether his $35m assets - said to include a Bombardier private jet and property in London - were obtained illegally.
The law permits police in Britain to apply for suspect monies to be frozen in the pre-trial stage of a criminal investigation.
Enquiries are simultaneously continuing in Nigeria.