In 2008, famous tennis player John McEnroe was scammed for about $88 millions by art dealer Lawrence Salander. The art dealer had received cash in exchange for shares of ownership from John McEnroe and a few others. Renaissance Art Investors had invested $45 million, Earl Davis, son of American painter Stuart Davis had invested $6.7 million, along with Bank of America which had made an investment of $2 million. Salander had operated this investment scam with paintings that are not his own. He had also directed the investment money into fallacious schemes. McEnroe was scammed by $2 million. He had invested half share in two paintings that did not belong to Lawrence Salander.
These kinds of fake art deals happen a lot. As an investor or a buyer, you need to check well in advance on whether the dealer is authentic, the painting is original etc.
(Via Fraud and Scam news)