The former Russian nuclear energy minister was arrested in Bern, the Swiss capital, on May 2 this year, at the request of the U.S. Justice Department.
The Federal Court in Lausanne has concluded that the ex-minister entered the country as a private individual and was not afforded any immunity as a foreign witness.
Other arguments being put forward by Adamov's defense team to prove that his arrest was illegal are now to be considered by the Federal Criminal Court in Bellizona. The lawyers claim Adamov should be immune from prosecution because he is a former senior government official and because the U.S. case against him is politically motivated.
The Bellizona Court will also be looking into the defense team's appeal against Adamov's second arrest, which was at the request of the Russian authorities. The appeal was filed on June 17.
Under the ruling of the Lausanne Court, Adamov shall remain in Swiss custody until the Federal Justice Department makes a decision on his extradition. The ex-minister can still use his right to opt for a simpler extradition procedure, but if he does not, it will be up to the Justice Department to decide whether he should be handed over to the U.S. or to Russia.
The U.S. made its extradition request on June 24. The Americans accuse Adamov of misappropriating $9 million that was allocated for nuclear security programs in Russia.
Russia submitted its extradition request to Switzerland on May 17, after initiating legal proceedings against Adamov on charges of fraud and abuse of his office.