The offices of Russian state-owned diamond monopoly Alrosa were raided by the Federal Security Service (FSB) on April 6 as part of an investigation into the sale of non-core assets.

“Law enforcement agencies were seizing documents at Alrosa’s head office in Moscow, following a request by investigators in Yakutia,” reports VTB Capital.

The action relates to non-core asset sales, specifically the 2015 sale of 85% of MAK-Bank for the undisclosed price, Vedomosti reports.

The raid comes as part of a growing trend as the government continues its crackdown on corruption, increasingly focusing on Russia’s regions.

Earlier this year Tatfondbank, a large bank in Tatarstan, was closed by the Central Bank of Russia (CBR) and several of its management team arrested on corruption charges. 

On April 4 yet another Russian governor was arrested on suspicion of taking a RUB140mn ($2.5mn) bribe in the Kremlin’s latest high-profile anti-corruption sting operation. Alexander Solovyov, the head of Russia’s central republic of Udmurtia, faces 15 years in prison if found guilty of large-scale corruption.

Separately, Mining.com reported that the Alrosa investigation was into asset sales in 2011-2013, including a 51% stake in Timir iron ore project to Evraz and the ultimately unsuccessful negotiations with Russian oil giant Rosneft to offload the diamond miner’s gas fields.

Alrosa has become a darling of portfolio investors since it was partially privatised last year and more shares are due to be sold, possibly this year, as part of the government’s privatisation programme.

The company remains majority-owned by the Russian government and the far eastern province of Yakutia (Sakha), which is home to its large diamond deposits. The government sold a 10.9% stake in the company last year raising $813mn for the state coffers.

The company posted a four-fold increase in profits to RUB133.5bn ($2.31bn) in 2016 after the demand from the crucial Indian market improved unexpectedly.

Alrosa’s 2016 revenue increased by 41% y/y and totalled RUB 317.1bn. Ebitda grew by 49% y/y to RUB 176.4bn, with Ebitda margin totaled 56%. Net income surged fourfold y/y to RUB 133.5bn. Free cash flow increased threefold to RUB 111.4bn, the company said in a statement on its website.

“2016 was a year of active recovery in the diamond market following the decline of 2015. The Company managed to deliver record-high financial performance and generate net cash flow sufficient to repay short-term and medium-term liabilities and pay out dividends to shareholders,” said Igor Kulichik, Alroasa’s vice president and chief financial officer.

The state’s overseer for Alrosa, Deputy Yrime Minister Yury Trutnev, who is also President Vladimir Putin’s envoy to the Russian Far East, was informed of the investigation.