The joy must have been palpable in 2013 when three New York art traders arranged through Sotheby’s to sell a newly discovered painting by Leonardo da Vinci, the Renaissance master, for $80 million.

One of them had purchased it at an estate sale for less than $10,000 eight years earlier, when most experts viewed it as only the work of Leonardo’s school.

But the traders’ joy later soured, according to court papers, when they learned that the man who bought it, an important Swiss art dealer, had turned around and sold the painting within days to a Russian billionaire for $47.5 million more.

The traders asked Sotheby’s, according to court papers, whether it had been aware that there was a much higher price to be had for the painting.