Russia’s central bank revoked medium-sized Moscow-based Master Bank’s license for “large-scale dubious operations,” suggesting the central bank may be planning a fuller crackdown on the country’s banks.

Master Bank is only Russia’s 41st-largest bank and holds about $1 billion in individual deposits, but it was a top-five ATM operator and a plastic card issuer, and one of President Vladimir Putin’s cousins is a member of Master Bank’s board.

The bank’s shutdown is the central bank’s most high-profile move since its first female governor, Elvira Nabiullina, took office in July.

Nabiullina said this week that Master Bank had a negative capital of about $61 million and was involved in illicit activities.

"The bank concealed its real condition, submitting substantially false reports," Nabiullina told the Duma, Russia’s lower house of parliament, on Wednesday. "The bank was involved in servicing the shadow sector of the economy, illegal transactions and repeated violations of money-laundering laws. We were forced to take this as last-resort measure."

The central bank has closed smaller banks on similar grounds in recent years, but Master Bank is the largest to have its license revoked since the crisis of 2009-2009.

Russian police had been investigating Master Bank for the past year, according to the Wall Street Journal and Bloomberg.

A Livejournal blogger by the username dr_crisis wrote in March that “hundreds of Master Bank's armored trucks full of black market cash drive around Moscow ... Every morning there is a line of people at the bank's office on Pyatnitskaya with sacks for cash, and all this is happening in Moscow's plain sight."

Bankers who agreed with the blogger speculated that the government allowed Master Bank to operate because of its ties to Putin, Bloomberg reported. The president’s cousin Igor Putin worked at Master Bank as the vice president and then a board member. A Kremlin spokesman told the media that the cousin has no ties to the president other than his name. 

Nabiullina’s predecessor at the central bank, Sergei Ignatiev, said in a February speech that wide-scale money laundering plagued the Russian banking system.

A former central bank deputy governor, Sergei Aleksashenko, tweeted Wednesday that Master Bank was the result of Ignatyev’s 11 years of inaction in the field of bank supervision.