Swiss businessman Yves Bouvier, the head of art storage, shipping, and servicing company Natural Le Coultre, as well as the Geneva, Luxembourg, and Singapore freeports, has been arrested in Monaco on suspicion of defrauding art collectors.

Bouvier’s alleged victims are said to include a number of wealthy individuals in the US, Asia, and the UK, including Russian oligarch Dmitry Rybolovlev, owner of the Monaco football club. With a net worth estimated at $8.5 billion and an art collection that includes Picasso, Vincent van Gogh, Paul Gauguin, and Claude Monet, Rybolovlev is listed by Forbes as the world’s 160th wealthiest person—even after his ex-wife was awarded half of his fortune in their 2014 divorce settlement.

“After having worked for more than ten years with Mr Bouvier, the Rybolovlev family received some information about possible fraud and manipulation of prices on the art market by Mr. Bouvier and his accomplices,” said Tetiana Bersheda, the Rybolovlev family lawyer, in a statement. The scope and all the victims of the fraudulent scheme created by Mr Bouvier have not yet been identified at this juncture,” the statement said. A source told the Telegraph the Rybolovlevs may be out tens of millions of euros.

Last year, Bouvier opened Le Freeport in Luxembourg (see “Le Freeport” Opens in Luxembourg). The freeports, which count the Nahmad family among their clients (see No, Helly Nahmad Is Not Hiding a $20 Million Nazi-Looted Modigliani), have come under fire for serving as tax havens that allow wealthy collectors to lock art away from the public view. Anne Klein of theater collective Richtung22, which put on a satirical play about the freeports, told the Independent, she was “appalled to see art being transformed into a mere item of speculation. Locked away in the freeport, art loses its purpose.” “It’s conspicuous consumption at its worst, the rich showing off to the rich, and it’s socially obnoxious,” added John Christensen of the Tax Justice Network.

Bouvier is also the backer for the Jean Nouvel-designed R4 art hub planned for Paris’s Île Seguin (see Paris Will Get €150 Million Jean Nouvel-designed Art Island).