Angola's chief prosecutor on Friday said funds that Isabel dos Santos - who is accused of stealing millions of dollars from state companies - invested in Portugal had been embezzled from her home country.
"Angola believes that the money used for business conducted by Isabel dos Santos in Portugal left Angola by illicit means," Helder Pitta Gros told the RTP television station on a trip to Lisbon.
The accusation comes a day after the tycoon daughter of Angola's ex-president Jose Eduardo dos Santos vowed she would fight what she called "misleading and untrue" allegations which have stretched across Angola's state oil and diamond industries and banks to Lisbon.
Angola's prosecutors accuse Dos Santos of financial crimes during her tenure at Sonangol, Angola's state-owned oil giant which she headed during her father's rule, and charged her with money laundering, influence peddling, harmful management, forgery of documents and more.
Much of the allegedly misappropriated money was invested in Portugal, prosecutors believe.
Gros said this week that Dos Santos was among five named suspects, all of them residing abroad.
Angolans call her "the princess", and she is Africa's richest woman according to Forbes, which estimates her assets at $2.1bn.
Hundreds of companies, many based in tax havens such as the British Virgin Islands, are alleged to have helped Dos Santos accrue her fortune.
The mounting scandal has prompted scrutiny in Portugal and some of its corporations, especially the small lender EuroBic.
EuroBic banker Nuno Ribeiro da Cunha, who local media named as Dos Santos's account manager, was found dead at his home by police in Lisbon on Wednesday night.
He had been identified in a worldwide media release of documents, dubbed the "Luanda Leaks", and was one of the five suspects named this week.
The leak of more than 715 000 files, published on Sunday by some of the world's top media outlets, suggest the alleged looting was systemic.
Just hours before Da Cunha's apparent suicide, Eurobic said that Dos Santos had decided to sell her shares in the lender.
Dos Santos has repeatedly denied any wrongdoing and denounced the investigations as politically motivated.
Portugal's energy and electrical engineering group Efacec has also announced that Dos Santos wanted to pull her capital out of the company.
In 2015, she bought 65% of Efacec, prompting calls by European Union parliamentarians to investigate the source of her funding.
The 46-year-old businesswoman has been furiously defending her empire, claiming her fortune was built on nothing but hard work and fruitful investments.
Angola is still reeling from ex-president Dos Santos's 38-year rule, during which key positions were awarded to his cronies and wealth amassed by a select few.
Angolan President Joao Lourenco - Jose Eduardo dos Santos's anointed successor - has vowed to crack down on corruption and has launched a large-scale purge of the Dos Santos administration.
Angola is a former Portuguese colony which gained its independence in 1975 after the fall of Portugal's dictatorship the previous year, along with the fellow African colonies of Mozambique, Cape Verde, and Sao Tome and Principe.