EuroBic
© Patrícia de Melo Moreira/AFP via Getty Images
EuroBic is a privately–owned lender whose largest shareholder is Dos Santos.
A senior manager at a Portuguese bank co-owned by Isabel dos Santos, the Angolan businesswoman at the centre of the Luanda Leaks scandal, has been found dead in Lisbon.

The death of Nuno Ribeiro da Cunha, 45, was confirmed by police hours after the banker was named alongside Dos Santos and three other individuals as a suspect in a criminal investigation in Angola into alleged embezzlement at the state oil company, Sonangol.

The national director of Portugal's judicial police, Luis Neves, said preliminary reports indicated Ribeiro da Cunha's death was suicide and that nobody else was involved. He told reporters his staff were prepared to help with the Angolan corruption investigation whenever a formal request is made.

The banker held a senior role at EuroBic, a privately-owned lender whose largest shareholder is Dos Santos. He appears to have handled a number of transactions for companies controlled by Dos Santos, according to leaked files.

Dos Santos, the daughter of Angola's former president, José Eduardo dos Santos, has faced intense pressure this week after the Guardian and other media published stories based on the Luanda Leaks, a cache of 715,000 papers from the heart of her business empire.

The documents, passed to the International Consortium of Investigative Journalists (ICIJ), reveals the complex financial schemes that helped Africa's richest woman amass a fortune at vast cost to the Angolan state.

Dos Santos denies accusations of nepotism and corruption and insists that her estimated $2.2bn (£1.7bn) fortune - which makes her the richest woman in Africa - is the result of legitimate business and says she is the victim of a politically-motivated "witch-hunt" by the new Angolan president.

Dos Santos issued further denials on Thursday, after it emerged she had been named as a criminal suspect in Angola, claiming "the rule of law has been undermined in Angola where the courts are subject to political pressure".

"The allegations which have been made against me over the last few days are extremely misleading and untrue," she said. "This is a very concentrated, orchestrated and well-coordinated political attack, ahead of elections in Angola next year."

She added: "I am a private businesswoman who has spent 20 years building successful companies from the ground up, creating over 20,000 jobs and generating huge tax revenue for Angola. I have always operated within the law and all my commercial transactions have been approved by lawyers, banks, auditors and regulators."

One of those auditors, the accountancy firm PwC, has terminated all work for entities controlled by the Dos Santos family, and initiated an investigation. The global chairman of PwC, Bob Moritz, told the Guardian heads could roll at his company. "We'll wait for the investigation, I don't want to rush," he said earlier this week. "But we need to move with speed to take action to regain confidence."

On Thursday, Angola's attorney general, Heldér Pitta Grós, travelled to Lisbon to discuss the Dos Santos case with his Portuguese counterpart, Lucilia Gago.

The Angolan criminal investigation by government prosecutors is focusing on the period Dos Santos spent at the helm of Sonangol. The state oil company accounts for 90% of exports in a country where millions live below the poverty line, earning less than $2 a day.

"Isabel dos Santos is accused of mismanagement and embezzlement of funds during her tenure at Sonangol," Pitta Grós said at a press conference on Wednesday evening.

He named four other individuals as suspects. They included Ribeiro da Cunha - the director of private banking at EuroBic who was found dead.

Earlier this week EuroBic announced that it had barred Dos Santos and her family as customers. On Wednesday it confirmed she had agreed to sell her 42.5% shareholding.

The Angolan authorities said they will now conduct a criminal investigation to determine whether Dos Santos and the other suspects should be formally charged. All those concerned will be notified of their status as defendants and asked to voluntarily return to Angola, said Pitta Grós.

He added international arrest warrants could he issued for those who do not come of their own accord.

In her statement, Dos Santos said "stolen documents" had been "leaked selectively to give a false impression of my business activities". She added: "It is an attempt to neutralise me and to discredit the legacy of president dos Santos and his family. No one should be taken in by these diversionary tactics."

Additional reporting by Sam Cowie