Russia's Sistema chairman under house arrest in Bashneft case
Sistema, which controls Russia's biggest mobile phone operator MTS, said it considered the charges against Yevtushenkov baseless.
The accusations followed a court order that prohibited Sistema from selling its shares in Bashneft earlier this year, due to an investigation that Sistema had said it was not party to.
They also came amid speculation that state-controlled Rosneft, Russia's biggest oil producer run by President Vladimir Putin's powerful ally Igor Sechin, was interested in buying Bashneft.
Russia's Federal Investigative Committee said on Tuesday it was looking into a criminal case over the theft of shares of oil companies in Bashkortostan, a Russian republic.
"Investigators have reasonable grounds to believe that Sistema Board Chairman Vladimir Yevtushenkov is involved in the legalisation of property acquired by criminal means. Today he was accused of money-laundering," the Investigative Committee said in a statement on its website.
Russian news agencies also reported Yevtushenkov had to stay under the house arrest until Nov. 16 and that his lawyers had three days to appeal against the Moscow Basmanny Court decision.
Sistema, which occupies a historic building in front of the Kremlin's walls, rejected the accusations.
"We believe the charges brought by Russia's Investigative Committee against AFK Sistema Chairman V.P. Yevtushenkov (to be) completely groundless and we will use all legal means to defend our position," it said in emailed comments.
MTS's New-York listed stock fell 4.8 percent on the news.
Since Sistema became the majority shareholder in 2009, Bashneft has shown one of the highest production growth rates among Russian oil companies, thanks to advanced recovery techniques used at its deposits.
Russian business daily Vedomosti reported in June that Rosneft was interested in buying Bashneft, but Yevtushenkov told Reuters at the time Sistema was not involved in negotiations to sell, while Rosneft would not comment on the report.
The restrictions on Bashneft shares hampered plans for a share offering by the mid-sized oil company in London. Bashneft has been planning a market float since it was acquired by Sistema.
Yevtushenkov is ranked Russia's 15th richest man by U.S. magazine Forbes, with an estimated fortune of $9 billion (5.53 billion pounds).
(Reporting by Maria Kiselyova; editing by Susan Thomas and Keiron Henderson)