The documents were filed last week with the Commercial Court of the High Court in London as part of the lawsuit by telecommunications company Unitel against Unitel International Holdings (UIH), owned by Isabel dos Santos, to recover a debt of over €350 million.

In the documents, seen by Lusa news agency, the lawyers said they had used the services of Israeli private investigation agency Black Cube to “expose those responsible for the actions against dos Santos and their motivations,” and cited several people close to the Angolan administration.

“The Black Cube investigation revealed that the new administration is the source of the Luanda Leaks, having been the orchestrator and executor of the illegal access of Mrs Dos Santos’ servers, as well as her associates and service providers, including law firms commissioned on her behalf,” they read.

The investigators cited as a source Mirco Martins, stepson of the former president of Sonangol, Manuel Vicente, who is said to have said that “the documents were delivered by the new Angolan administration to a Portuguese (Rui Pinto) through the intermediary of the then Angolan Minister of Foreign Affairs, Manuel Augusto.

Martins reportedly said: “Our Secret Service gave the information ... to MA (Manuel Augusto)” and “the Secret Service gave it to screw Isabel dos Santos”.

The accusations are part of a document with additional information to contest Unitel’s accusation, in which the lawyers of the former president of Angola José Eduardo dos Santos claim that Isabel dos Santos is the victim of persecution by President João Lourenço.

The recordings also quote N’gunu Tiny, an Angolan businessman and lawyer who worked at CFA Advogados, an office that represents Sonangol, Inocêncio das Neves, nephew of the spokesman and advisor to President Lourenço, Luís Fernando, Leandro Laborinho, son of the Interior Minister, Eugénio César Laborinho, and Sonangol director Carlos Saturnino Guerra Sousa e Oliveira.

According to the lawyers, Black Cube was initially hired to “investigate the circumstances that led to the outcome in the ICC Arbitration between Unitel shareholders” in late 2017, and that was then “expanded to expose those responsible for the actions against dos Santos and their motivations”.

Questioned by Lusa, a lawyer for the Angolan businesswoman said that “the evidence presented to the High Court in London was collected by entirely legal means” and that the operational procedures and methodologies were done according to the guidance of legal advisors.

“Black Cube was hired due to its experience in information gathering and analysis, specifically in supporting court cases and arbitrations of extraordinary complexity and international scope,” Michelle Duncan said.

The International Consortium for Investigative Journalism (ICIJ) revealed in January 2020 more than 715,000 files, under the name Luanda Leaks, detailing alleged financial schemes by Isabel dos Santos and her husband, Sindika Dokolo, who has since died, that are said to have allowed them to take money from the Angolan public purse through tax havens.

According to the journalistic investigation, which in Portugal includes Expresso newspaper and SIC, Isabel dos Santos is said to have set up a scheme that allowed her to divert more than US$100 million (90 million Euros) to a Dubai-based company, Matter Business Solutions.

Rui Pinto is on trial in Portugal as part of the Football Leaks case, having been accused of crimes of improper access, violation of correspondence and illegitimate access targeting entities such as Sporting, Doyen, the law firm PLMJ, the Portuguese Football Federation (FPF) and the Attorney General’s Office (PGR).