Russian businessman Vladislav Klyushin was arrested in Switzerland in March on a Justice Ministry order after he flew into the country on a private jet for a family skiing holiday.

Klyushin is suspected of meddling in the 2016 U.S. presidential election. FBI investigators say he and his accomplices hacked U.S. companies to steal sensitive data, which they then used to raise tens of millions of dollars in the stock markets.

He led the Russian intelligence operation to influence the electoral process and was also involved in hacker attacks on the servers of the US Democratic Party, which later lost to the Republicans.

The case is pending in a Massachusetts court, the materials are classified.