An investigation has turned up new information about the shady deals that made Roman Abramovich wealthy. In 1995, the Chelsea owner made billions by purchasing an oil company from the Russian government in a rigged auction.

Mr. Abramovich paid approximately $250 million (£190 million) for Sibneft before selling it back to the Russian government for $13 billion in 2005.

According to his lawyers, there is no basis for alleging that he has amassed significant wealth through criminal activity.

The UK government sanctioned the Russian billionaire last week due to his ties to Russian President Vladimir Putin.

Mr. Abramovich’s assets have been frozen, and he has been removed from the board of directors of Chelsea Football Club. In a UK court, the Russian billionaire admitted to making corrupt payments to help get the Sibneft deal off the ground.

Boris Berezovsky, a former business associate, sued him in London in 2012.

Mr Abramovich won the case, but in court he described how the original Sibneft auction was rigged in his favor and how he gave Mr Berezovsky $10 million to pay off a Kremlin official.

A document believed to have been smuggled out of Russia has been obtained by BBC Panorama.

A confidential source told the program that the information was secretly copied from files held on Mr. Abramovich by Russian law enforcement agencies. The investigation cannot confirm that, but checks with other Russian sources have confirmed many of the details in the five-page document.

According to the document, the Russian government was duped out of $2.7 billion in the Sibneft deal, which is supported by a 1997 Russian parliamentary investigation. According to the document, Russian authorities wanted to charge Mr. Abramovich with fraud.

According to the report, “the Department of Economic Crimes investigators concluded that if Abramovich could have been brought to trial, he would have faced accusations of fraud… by an organized criminal group.”

Panorama tracked down Russia’s former chief prosecutor, who was involved in the investigation of the deal in the 1990s. Yuri Skuratov was unaware of the secret document, but he independently confirmed many details surrounding the Sibneft sale.

“Basically, it was a fraudulent scheme, where those who took part in the privatization formed one criminal group that allowed Abramovich and Berezovsky to trick the government and not pay the money that this company was really worth,” Mr Skuratov said on the program.

According to the document, Mr. Abramovich was also shielded by former Russian President Boris Yeltsin.

According to the report, law enforcement files on Mr. Abramovich were transferred to the Kremlin, and Mr. Skuratov’s investigation was halted by the president.

Mr. Abramovich formed a joint venture with another company to purchase Slavneft, but a rival Chinese company planned to bid nearly twice as much. Many powerful people, from the Kremlin to the Russian parliament, stood to lose if the Chinese won the auction.

According to the document, a member of the Chinese delegation was kidnapped upon their arrival in Moscow for the auction.

“CNPC, a Chinese company and a strong competitor, was forced to withdraw from the auction after one of its representatives was kidnapped upon arrival at Moscow Airport and was only released after the company declared its withdrawal. 

The kidnapping story is supported by independent sources who were unaware of the document.

In the run-up to the Slavneft sale, Vladimir Milov was Russia’s deputy energy minister. He didn’t address the kidnapping story, but he did say that senior political figures had already decided that Mr. Abramovich’s partnership would win the auction.

There is no evidence that Mr Abramovich was aware of the kidnapping plot or played any role in it.

Different factions were vying for control of Slavneft, and the Chinese bid was met with widespread opposition.

Whatever the reason for China’s withdrawal, Mr. Abramovich’s partnership was the only one left on the table. They also paid a low price for Slavneft.

Mr. Abramovich’s lawyers claim that allegations of corruption in the Slavneft and Sibneft deals are false, and he denies that Mr. Yeltsin shielded him.