A banker implicated in the embezzlement and money-laundering case against Africa's richest woman, Isabel dos Santos, has been found dead in Lisbon. Nuno Ribeiro da Cunha, 45, managed the account of oil firm Sonangol, formerly chaired by Ms Dos Santos, at the small Portuguese lender EuroBic. His death, on Wednesday, was reported on Thursday soon after Angolan prosecutors named both as suspects. Ms Dos Santos denies alleged corruption revealed by leaked documents. Mr Da Cunha was found dead at one of his properties in Lisbon. A police source told Portuguese media that “everything points to suicide”. Local media quoted police as saying Mr Da Cunha had already attempted to kill himself this month and had been suffering from depression. On Wednesday EuroBic said it would end its business relationship with Ms Dos Santos, who is reportedly the bank's main shareholder through two companies she owns. It was later reported as saying that Ms Dos Santos was selling her capital stake in the bank. The bank added that it would investigate transfers worth tens of millions of dollars she had made. Some of the transfers drained Sonangol's account at EuroBic, the New York Times reports. What is Dos Santos accused of? Prosecutors are seeking to recover $1bn (£760m) that Ms Dos Santos and her associates are alleged to owe the state. “Isabel dos Santos is accused of mismanagement and embezzlement of funds during her tenure at Sonangol,” Mr Pitta Gros told a news conference on Wednesday evening. He said that as a result, she was being provisionally charged with “money laundering, influence peddling, harmful management… [and] forgery of documents, among other economic crimes”. The Angolan authorities will now conduct a criminal investigation to determine whether she should be formally charged. They have also named five other people as suspects in the case, one of whom was Mr Ribeiro da Cunha, and urged them to return to Angola. Mr Pitta Gros said that if Ms Dos Santos did not return to Angola voluntarily, an international arrest warrant would be issued for her. Ms Dos Santos was controversially appointed head of Sonangol in June 2016 by her father, the then president of Angola. She was sacked from the post in 2017 by her father's successor, President Joao Lourenço. An investigation into Ms Dos Santos was opened after her successor at Sonangol, Carlos Saturnino, alerted authorities to alleged irregular money transfers. Her assets in Angola have been frozen. What is in the leaked documents?