Prosecutors in Angola have accused Isabel dos Santos of a range of offences including fraud, embezzlement and money laundering, urging her to return to the country to potentially face criminal proceedings.
The allegations are linked to dos Santos’ stint as chairwoman of Angola’s state-owned oil firm Sonangol, according to the country’s Attorney General, Helder Pitta Gros.
Dos Santos, who revealed earlier this month that she was considering running for the Angolan presidency in the next elections, denies all accusations and claims that the charges are a political ploy.
Pitta Gros has said that an international arrest warrant could be issued for dos Santos if she fails to return to Angola.
Isabel is the daughter of Jose Eduardo dos Santos, who served as Angolan president for 38 years. Jose Eduardo stepped down as president in 2017, but not before appointing his daughter as Sonangol chair in June 2016.
After Jose Eduardo handed the presidency over to his successor, Joao Lourenço, the country's new leader sacked Isabel dos Santos from her position at Sonangol.
Investigations were then opened into Isabel's business dealings and her assets in Angola frozen after her successor as chair, Carlos Saturnino, uncovered irregular money transfers from the oil firm's accounts made during her tenure.
Isabel's half-brother is currently standing trial in Angola as part of the wider case.
Business documents leaked this week have reportedly shown how Isabel dos Santos had access to land, oil, diamond and telecoms deals during her father’s term, as well as how she used Western companies to smuggle money out of Angola.
Her fortune is estimated to be worth £1.6 billion, with prosecutors looking to recover £760 million worth of funds believed to have been stolen from the state.
Pitta Gros told the media this week: "Isabel dos Santos is accused of mismanagement and embezzlement of funds during her tenure at Sonangol", adding that she was being provisionally charged with "money laundering, influence peddling, harmful management, forgery of documents, among other economic crimes".
Elsewhere, Nuno Ribeiro da Cunha, who managed Sonangol’s accounts at Portuguese bank EuroBic, was found dead at his Lisbon residence earlier this week, suspected to have committed suicide.
Ribeiro da Cunha was one of five other suspects named in the investigations who prosecutors called on to return to Angola.
On Wednesday, the same day Ribeiro da Cunha's body was found, EuroBic announced that its business relationship with Isabel dos Santos would be terminated and investigations would commence into tens of millions of dollars worth of transfers that she had made from Sonangol's account.
Following the announcement, it was reported that Isabel dos Santos would sell her stake in EuroBic. She is thought to have been the bank's primary shareholder via two of her companies.