(Bloomberg) -- Russian billionaire Mikhail Fridman claimed that a police raid on his London mansion in December for alleged sanctions evasion was illegal and relied on “kompromat” including a 15-year-old report that made a series of unproven criminal allegations.

At a London court hearing Thursday, Fridman’s lawyers argued the National Crime Agency misled judges when it applied for a search warrant last year by overly relying on the 2007 report compiled by a private firm. The NCA’s lawyers have accepted that the warrant should be quashed but want to continue the agency’s investigation for sanctions evasion.

Stratfor, a private intelligence firm, alleged in the report that US investigators claimed Fridman’s Alfa Group made illegal payments to Saddam Hussein during its oil-for-food program in Iraq, funded one of Russia’s largest organized crime networks and laundered money on behalf of Colombian drug cartels, among other unproven claims.

“None of the allegations of serious criminality had ever been substantiated by any reputable law enforcement agency,” Fridman’s lawyers argued in court filings. “The allegations were absolutely typical of classic kompromat – damaging and untrue information assembled and used to create negative publicity and to exert influence over the subject.”

The UK government imposed sanctions on Fridman in March 2022 just weeks after President Vladimir Putin launched his full-scale invasion of Ukraine. It alleged that he is a “pro-Kremlin oligarch” but it did not rely on the Stratfor report as part of the sanction designation, Fridman’s lawyers said. 

Fridman is the founder and main shareholder of Alfa Group, which includes Russia’s largest private bank. He moved to London in 2013 after he and his partners sold their stake in TNK-BP to state-controlled oil giant Rosneft, pocketing $14 billion.

The raid on the banking tycoon’s home was the most high-profile action by the National Crime Agency’s Combatting Kleptocracy Cell into allegations of money laundering and sanctions evasion since the invasion. The NCA has said the search warrant was unlawful and that the copy left at the premises was unsigned and had the wrong date, according to legal documents seen by Bloomberg. 

An NCA spokesperson said earlier this month that the agency accepted the warrant contained “technical errors.” 

The agency has been investigating Fridman over an alleged loan payment from his Alfa Bank to his executive assistant before he was sanctioned, according to the tycoon’s court filing. The agency wants approval to access mobile phones and tablets seized in the raid to continue its investigation.

The judges ruled a full hearing will be held in November, saying that the seized devices couldn’t be inspected until after that date.

More than 50 NCA officers descended on Fridman’s north London mansion in December wearing body armor and helmets. Some officers entered the property by climbing over a side gate using ladders and deployed a battering ram to force open the gate. NCA officers seized Fridman’s electronic devices and computers as well as passports, family photographs and documents.

The NCA has already dropped an investigation into allegations Fridman conspired to defraud the Home Office in connection with his partner’s UK residence permit application, and a probe related to a conspiracy to commit perjury concerning the address on his daughter’s birth certificate.

(Updates with decision from judges in 10th paragraph)

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