Agents of Russia's Federal Security Service (FSB) have raided the Moscow offices of a company controlled by billionaire oligarch Mikhail Prokhorov.
The FSB said on April 15 that the search of ONEKSIM's office happened the previous day and was part of an ongoing tax-evasion investigation.
Russian media have speculated that the search was retaliation against Prokhorov for reports published by his online media resource RBK.
RBK was one of the few Russian media outlets to give ample coverage to the allegations against Russian officials that were part of the Panama Papers leak.
Prokhorov also owns the Brooklyn Nets NBA basketball team in the United States.
Russian President Vladimir Putin's spokesman, Dmitry Peskov, denied that there was any link between the tax investigation and RBK's reports.