The Russian Investigative Committee has failed to file formal tax evasion charges against Hermitage Capital head William Browder because he did not show up for questioning, a spokeswoman said on Thursday.
"If he fails to appear again, action will be taken to establish his whereabouts and enforce his presence," committee spokeswoman Irina Dudukina said.
U.S.-born Browder, who is a British citizen, is suspected of underpaying more than 2 billion rubles ($72 million) in back taxes.
He was once one of the most successful Western investors in Moscow but was banned from Russia in 2005, ostensibly for national security reasons, and now lives in Britain.
Dudukina said there were no impediments to Browder's entry into Russia and he could easily receive a visa if he applied.
According to some media reports Russia will seek Browder's extradition and prosecute him in absentia if Britain refuses.
Hermitage Capital has been in the focus of a controversial tax evasion case that led to the death in custody of lawyer Sergei Magnitsky in 2009.
Magnitsky was jailed in 2008 after being charged with tax evasion linked to his defense of Hermitage Capital.
The lawyer accused Russian tax and Interior Ministry officials of using documents seized form Hermitage's subsidiaries to register their own people as owners and directors and file a false tax claim to embezzle $230 million.
He died aged 37 from acute heart failure after 11 months in a Moscow pre-trial detention facility.
Magnitsky was kept in appalling conditions and was refused crucial medical treatment in what Hermitage says was an effort to coerce him to admit his role in its alleged tax evasion.
MOSCOW, May 12 (RIA Novosti)
