Billionaire Vladimir Evtushenkov, Russia’s 19th-richest person, was placed under house arrest today on suspicion of money laundering in a case linked to OAO Bashneft, an oil producer controlled by his AFK Sistema.

Russia’s Investigative Committee opened a criminal probe into the alleged seizure of shares in energy assets in Bashkortostan, a republic between the Ural Mountains and the Volga River where Bashneft is based, according to a statement on the website of the law-enforcement agency. Sistema said the accusations were “completely groundless” and vowed to use all possible legal means to make their case.

Evtushenkov has a fortune estimated at $6.9 billion, according to the Bloomberg Billionaires Index. Another tycoon, Mikhail Khodorkovsky, was arrested in 2003 as head of Yukos Oil Co. and Russia’s richest man at the time. His company since dismantled, Khodorkovsky was released in December after a decade in prison.

Evtushenkov’s holding company Sistema in 2009 bought a controlling stake in Bashneft, which produces about 350,000 barrels of oil a day. In April, Russian investigators opened a case linked to deals with Bashneft shares in 2002-2009, Sergey Makarenko, a lawyer for a former president of the Bashkortostan region, said last month. Sistema’s shares in Bashneft were frozen in July.

Open, Fair

The acquisition of Bashneft was “open and fair” and the company is cooperating with the investigation, Sistema Chief Executive Officer Mikhail Shamolin said during an Aug. 28 conference call.

Evtushenkov has three days to appeal his house arrest, Interfax reported, citing Anna Fadeyeva, a spokesman for the Basmanny Court in Moscow. He’s been placed under house arrest until Nov. 16, according to the news service.

American depositary receipts of OAO Mobile TeleSystems, Russia’s largest mobile operator that’s controlled by Sistema, dropped 4.8 percent to $17.71 as of 2:11 p.m. in New York, the lowest since Aug. 7.

Sistema’s press office wasn’t able to provide contact details for Evtushenkov’s legal representative.