ARTICLE AD BOX
By Imogen Foulkes, David Thompson & James Oliver
In Geneva and London
A trial of four former executives at the Zurich branch of Russia's Gazprombank has begun in Switzerland.
The three Russians and one Swiss are charged with helping Russian musician Sergei Roldugin launder funds suspected of belonging to Russia's president.
Mr Roldugin reportedly placed $50m (£42m) in Swiss accounts between 2014 and 2016, with no credible explanation of where the money had come from.
At the time, he presented himself as a cellist on a modest income.
He had become famous as a musician but did not earn vast sums. He once told the New York Times he was no businessman, and certainly not a millionaire.
So where did he get millions of dollars to put into Swiss bank accounts?
This is the question Zurich prosecutors say the accused former bankers should have asked. It was well known the cellist was a close friend of Russian President Vladimir Putin, and is even rumoured to be godfather to Mr Putin's daughter.
Under Swiss law, banks are required to reject or close accounts if they have doubts about the account holder, or the source of the money.
They are also supposed to handle "politically exposed persons" with extreme care. As a known friend to the Russian leader, investing millions in Switzerland after the illegal annexation of Crimea and subsequent sanctions against Russia in 2014, Sergei Roldugin should have rung alarm bells. Prosecutors will allege that did not happen.
The case is being seen as a test of how rigorously Switzerland enforces its money laundering laws, which, on paper at least, are quite strict.
Swiss authorities have worked hard in recent years to move away from the image of Switzerland as a country in which even the dirtiest money from the most brutalist dictator or most corrupt businessman can be washed whiter than white.
Mr Roldugin's questionable money was first revealed, not by Swiss investigators, but by journalists, including a team from BBC Panorama, involved in an international investigation of the Panama Papers data leak organised by the International Consortium of Investigative Journalists in 2016.
They discovered evidence of suspicious transactions involving Mr Roldugin's offshore companies worth hundreds of millions of dollars, as well as his Swiss bank accounts.
Only after that evidence appeared did Swiss prosecutors launch their own investigation. Their indictment, now before the court in Zurich, suggests the musician was acting as "Putin's wallet", channelling funds via bogus companies in Cyprus and Panama into Gazprombank in Zurich.
The four accused are charged with failing the "due diligence" test, in not checking - or turning a blind eye to - the real source of his money. They have all pleaded not guilty.
Gazprombank has since wound up its operations in Switzerland, and Sergei Roldugin himself is on the Swiss sanctions list.
But, if convicted, the four bankers face only mild, suspended jail terms of up to seven months. To secure a guilty verdict at all, prosecutors will have to convince the court that the Roldugin millions in fact belonged to Vladimir Putin.
Not an easy task now that the usual co-operation between states - in this case Switzerland and Russia - on money laundering investigations is not happening.
No-one really knows how much President Putin, and those close to him, actually have. His stated salary is only a little over $100,000 (£84,400), the Swiss indictment points out.
But there are rumours his fortune could be worth a staggering $125bn (£105bn), carefully stashed away in a complex web of shell companies and accounts of friends like Sergei Roldugin.
That's why, despite the modest sentences, a guilty verdict could be so significant. It would send a signal not only to Russia's president, his friends, and the rest of his political establishment, that their cash can no longer be so easily hidden, but also to the professionals who have administered their funds.
"Roldugin is not alone in his alleged role as one of 'Putin's wallets'," said Tom Keatinge, head of the Centre for Financial Crime and Security Studies at the Royal United Services Institute.
"Those banks and law firms providing services to other close connections of Vladimir Putin should be on notice that the authorities are clearly energised to make their case in court."