When Leonardo da Vinci's ethereal "Salvator Mundi" sold for a record-smashing $450 million last fall, a year-long federal investigation into a Swiss art dealer's mark-ups of artworks sold to a Russian billionaire seems to have evaporated.

A longstanding dispute between fertilizer magnate Dmitry Rybolovlev and his art dealer, the "freeport king" Yves Bouvier, over allegedly inflated prices of art, pulled in Sotheby's, a string of witnesses, and has caused legal drama worldwide for years. But the case in New York suddenly lost its luster when Christie's sold the da Vinci for $320 million more than Rybolovlev paid for it.

A bit of intrigue remains on the U.S. side of the case, as Bloomberg reports:

Rybolovlev’s prior contact with Trump was also a concern, according to a person familiar with the matter. First, the Palm Beach mansion sale [from Donald Trump to Rybolovlev] raised eyebrows because the sale price was twice what Trump had paid for it just four years earlier. Then, in the spring of 2017, it emerged that Rybolovlev’s private plane had turned up at airports in the U.S. where Trump was holding campaign events during the 2016 election.

Although Trump and Rybolovlev have said they never met, pursuing a case where the victim is a Russian oligarch who’s had dealings with Trump could have undercut the case with a jury, the person familiar with the matter said.