Nikolai Vasilyev, who led the team from the St Petersburg Mining University for the Vostok breakthrough last week, insisted that "absolutely nothing fell into the lake".

BBC: 'New frontier' of Antarctic lake exploration

Ellen Podgor, an expert in white-collar crime at Stetson University in St Petersburg, Florida, reckons that Siemens confessed all not to minimise the fine it had to pay but to avoid being barred from business with the American government.

ECONOMIST: The Siemens scandal

Ella Paneyakh, a sociologist and legal expert at Russia's European University in St Petersburg, said the case illustrated how in President Vladimir Putin's Russia "they are getting very creative, interpreting the law very literally, in a way which does not correspond to the spirit of the law".

BBC: News

On returning to St Petersburg in 1990, Mr Putin spent a year as a university bureaucrat, then moved into city government, trying to woo foreign investors.

ECONOMIST: Russia��s Putin puzzle