Two dozen sites in Bavaria, Baden-Wuerttemberg, Schleswig-Holstein and Hamburg are being searched, Munich prosecutors said in statement. They’re probing a Russian citizen who is on the sanctions list. While no names where disclosed, the target is Usmanov, a person familiar with the matter said. Hundreds of officers from various tax and police departments are involved.

German news media reported that Usmanov was targeted for tax evasion.

“The fact that these claims have only now emerged raises the legitimate question regarding the reason for such an attack against a law-abiding taxpayer,” a spokesperson for Usmanov said. “Any allegations of tax evasion by Mr Usmanov are unfounded, false and damaging to his honour, dignity and reputation, which Mr Usmanov will defend by all disposable legal means.”

Der Spiegel reported the raids earlier.

Usmanov is being investigated for sanctions violation because he allegedly kept and paid security staff to look after a luxury compound in Bavaria, according to the statement. The staffers are also being investigated.

Usmanov (69) owns a major stake in USM, a Russian investment group with holdings in Metalloinvest, one of the world’s largest iron ore producers, and telecommunications company MegaFon. He has a fortune of $17.8-billion, according to the Bloomberg Billionaires Index.

German authorities previously impounded Usmanov’s superyacht, Dilbar, after determining it was legally owned by his sister, Gulbakhor Ismailova, who is also subject to Western sanctions over the war in Europe. He has appealed the European Union sanctions at the EU’s General Court in April.

A different sister of the metals tycoon, Saodat Narzieva, was removed from the bloc’s sanctions list following a legal challenge.

Separately, Frankfurt prosecutors said they raided a 71-year-old Russian over money laundering allegations without identifying the man.