A former art dealer earlier convicted of tax fraud duped investors out of $6 million and used the money to buy cars, antique Japanese swords and valuable works of art, a prosecutor said during opening statements as the man's trial began in federal court Wednesday.

Rocco DeSimone has pleaded not guilty to mail fraud charges in the case. His defense attorneys declined to deliver an opening statement. But they wrote in a pre-trial court filing that they plan to argue that DeSimone's business dealings relied on information provided by his accountant, Ronald Rodrigues, who also had a financial interest in those dealings.

John McAdams, an assistant U.S. Attorney, told a jury in U.S. District Court in Providence that DeSimone convinced acquaintances and friends of friends to invest in inventions he said major international companies, such as Nintendo and Sony, had offered to buy for millions of dollars.