A Monaco court cleared on Tuesday the former head of Russia's atomic energy ministry of money laundering charges.
Ex-nuclear chief Yevgeny Adamov's co-defendant Mark Kaushansky and two Russian nationals were also cleared.
Adamov did not attended the hearings.
Adamov, who served from 1998 to 2001 as Russia's nuclear energy minister, was originally arrested in Switzerland in May 2005 at the request of the United States, where he was accused of misappropriating $9 million allocated to Russia for nuclear safety projects.
The investigation in Monaco began in 2001 after the Service of Information and Control of Financial Circuits (Siccfin) suspected him of laundering funds intended for the Russian nuclear industry.
The ex-minister was extradited to Russia in early 2006 to face an investigation into large-scale fraud and abuse of office charges and subsequent trial.
Adamov was sentenced to five and a half years in prison on fraud charges in February 2008. The Moscow City Court released Adamov after changing his jail term to a suspended sentence after just two months in custody.
Adamov returned to his post of scientific adviser at the Dollezhal Institute, one of Russia's largest nuclear research centers, where he has worked for around 20 years.
