Apparently there is nothing Donald Trump likes better than a good shouting match, even when it involves a lawsuit accusing him of fraud.

On Saturday, New York’s Attorney General, Eric Schneiderman, filed a civil lawsuit accusing Mr. Trump and his profit-making investment “university” of engaging in “persistent fraudulent, illegal and deceptive conduct.” The suit seeks restitution of at least $40 million for the 5,000 people across the country (including 600 New Yorkers) who were coaxed into “paying for a series of expensive courses that did not deliver on their promises,” according to Mr. Schneiderman’s statement.

Mr. Trump, of course, has not taken such accusations quietly. His organization quickly set up a Web site to blast Mr. Schneiderman for wasting taxpayer money and “conducting a no-holds-barred, scorched-earth investigation.” On television shows Monday morning, Mr. Trump claimed that students were 98 percent satisfied with the program. He also accused Mr. Schneiderman of being “a political hack looking to get publicity.”

The lawsuit accuses Mr. Trump and his organization of operating an unlicensed educational institution in New York from 2005 to 2011. Calling itself Trump University until May 2010, the operation did not have the license necessary under state law.