A Wall Street executive filed suit on Friday against what had been New York’s oldest art gallery, Knoedler & Company, charging that it and its former president, Ann Freedman, conspired with others in selling him a fake Willem de Kooning painting for $4 million. The suit is the third filed by an art collector involving a painting sold by the gallery, which closed last year.

In this case the executive, John D. Howard, asserts that the gallery paid only $750,000 for the painting in 2007 and days later sold it to him for more than five times that price. “No genuine work of art by de Kooning with a $4 million retail sale value could be purchased in good faith for $750,000,” the lawyers for Mr. Howard, from Lynn Cahill LLP, state in the papers filed in federal court in Manhattan. Mr. Howard’s suit asserts that his painting is one of a number of suspect works by Modernist masters that were supplied to the gallery by a little known Long Island dealer, Glafira Rosales. It states that the landscape, sold as a work painted by de Kooning in 1956-57, was probably created more recently by “someone affiliated with Rosales.”

The Federal Bureau of Investigation has been investigating the sale of paintings by Ms. Rosales. A lawyer for Ms. Rosales, Anastasios Sarikas, said she never intentionally sold artwork she knew to be forged. The gallery and Ms. Freedman have also denied any role in the sale of forgeries. “This is a copycat case which, like its predecessors, has no possibility of success,” said Nicholas Gravante Jr., Ms. Freedman’s lawyer. “We are prepared to demonstrate that the work at issue is genuine.” A spokeswoman for for the gallery said it would “vigorously defend the lawsuit and the baseless allegations.”