An anti-graft body says it has new evidence that Angolan President Jose Eduardo dos Santos received millions in kickbacks in the late 1990s, part of an allegedly dodgy debt repayment deal between Angola and Russia.
London-based Corruption Watch on Tuesday released a report detailing the involvement of Dos Santos, top oil officials and politicians in syphoning money off debt repayments to Russia through a middleman.
This new evidence was presented to prosecutors in Berne, Switzerland on Friday.
The organisation wants a new probe established into "a shocking case of deceit and deception by senior politicians, officials and dubious businesspeople, aided by international financial institutions, to rob their own citizens for personal gain."
In 1996 Russia granted Dos Santos's MPLA-led government -- at the time engaged in a bloody civil war -- a series of loans totalling $5 billion.
This was two thirds of Angola's entire annual economic output at the time and Russia agreed to accept a revised debt of $1.5 billion.
The money was repayed via an intermediary called Abalone Investments, formed entirely for that purpose by businessmen Arcadi Gaydamak and Pierre Falcone, known for "shady dealings" with Angola, the report said.
The company is accused of sifting off "as much as $750 million of Angolan government debt repayments," while redirecting some to individuals including Dos Santos, who received $36.25 million via front companies.
According to the report, Russia eventually accepted far less than the agreed debt amount "leaving even more in the hands of the middleman."
A previous investigation was dropped in 2004 in Switzerland.
"Each element of this complex transaction reinforces just how corrupt the deal was, a racketeering scheme of global scale, benefitting middlemen and elites in Angola and almost certainly Russia, with the aid of a major Swiss bank," says the report.
An Angolan government spokesman could not immediately respond to the allegations.
"Switzerland's banking system allowed this money to be stolen from one of the world's poorest countries," said David Mendes, an Angolan lawyer and opposition figure.
Corruption is rampant in the oil-rich southern African state, which ranked 157 of 174 countries in Transparency International's corruption perception index last year.
Despite this massive oil wealth which has seen some of the fastest growth in the world, large-scale misappropriation of public funds means the country remains deeply poor.