A California man pleaded guilty in federal court in Florida to charges that he tried to sell more than $6 million in counterfeit art, which he falsely claimed was created by the likes of Andy Warhol and Jean-Michel Basquiat, prosecutors said this week.

The man, Philip Righter, 43, forged documentation to support his claims of authenticity for fake paintings, and used the artwork as collateral for loans on which he later defaulted, the U.S. attorney’s office in the Central District of California and prosecutors in Florida said.

He also reported $2.6 million worth of art had been stolen, and falsely claimed to have donated art to a charity, leading to more than $100,000 in tax refunds, the California office said.

Mr. Righter was indicted last year in Florida on counts of wire fraud, mail fraud and aggravated identity theft in efforts to sell forged works by Basquiat and Keith Haring, as well as on other charges. He pleaded guilty on March 12 to one count of mail fraud and one count of aggravated identity theft in District Court for the Southern District in Florida, a statement from the U.S. attorney’s office there said.