Arkady Gaydamak, the Russian-Israeli tycoon best known in the UK as the father of the former Portsmouth FC owner Sacha, is suing one of Angola's top generals in the latest instalment of a multimillion-pound high court battle.
The case so far has heard evidence on themes ranging from arms deals to diamond trading, and has included bizarre stories, such as the destruction of a crucial document that was lodged for safekeeping with Russia's chief rabbi, Berel Lazar.
In the latest episode, General Manuel Hélder Vieira Dias Jr – known General Kopelipa – has been accused by Gaydamak of tricking and intimidating him into signing in 2011 a settlement deal with the billionaire diamond dealer Lev Leviev.
The settlement was struck in order to end a dispute between Gaydamak and Leviev that was that threatened to embarrass Angola's government because the state's diamond firm had teamed up with the Russian tycoons.
New high court documents filed by Gaydamak claim he signed the deal only after Kopelipa implied that Leviev had been instructed to pay Gaydamak compensation of $500m (£309m) in cash.
Gaydamak also claims the general offered him diplomatic immunity at a time when France was trying to extradite him to face charges of tax fraud. "General Kopelipa's position in Angola was such that it was in his power to prevent Mr Gaydamak from leaving Angola and to imprison Mr Gaydamak without cause or trial," the court documents allege. "In Angola, his word had the force of law."
In the end, Gaydamak did not receive cash or diplomatic immunity. He claims Kopelipa acted alongside Leviev in order to assist what he called the latter's "dishonest breach of trust". Gaydamak is suing both men in London for undisclosed damages.
The move comes after the failure of both Gaydamak's original $1bn claim against Leviev and an appeal last year, in which he alleged that his ex-business partner failed to pay dividends earned trading Angolan diamonds.
The first case enhanced the image of Gaydamak's colourful business career, including links to Angola's ruling People's Movement for the Liberation of Angola (MPLA), which emerged victorious after a 27-year civil war.
Gaydamak, who gave evidence to the high court via video link, as he would have faced extradition to France had he appeared in London, told the court last year that he forged close relationships with the Angolan government during its civil war, which ran from 1975 to 2002.
The tycoon constructed deals to sell the MPLA $70m worth of helicopters, and was involved in the "logistics and financing of the legal supply of arms, weapons and food to the official Angolan army".
He also said a document dating back to December 2001, allegedly outlining his and Leviev's diamond partnership, was entrusted to Lazar, the chief rabbi of Russia. Lazar said an envelope containing a document "might have [been] shredded by accident", while Leviev argued that there was no signed contract between the pair.
Apart from Kopelipa, Gaydamak's latest case sees him again suing Leviev as well as Carlos Antonio Sumbula, who heads Angola's state diamond company, Endiama, and who is alleged to have assisted Kopelipa with the settlement agreement.
Gaydamak's latest case against Leviev says he breached his duties as a trustee, a line of argument not explored in the first case.
Lawyers for Gaydamak declined to comment. The Angolan embassy in London and Endiama did not return calls or emails. Leviev's law firm, Stewarts Law, said: "We regard the claim as baseless and without merit."