NEW YORK (AFP) ― U.S. federal authorities are investigating whether paintings and drawings sold by elite New York art dealers as the work of Modernist masters are in fact fakes, The New York Times reported Saturday.

The pieces purported to be by artists like Robert Motherwell and Jackson Pollock, sold for up to $17 million apiece, were purchased through Glafira Rosales, a little-known art dealer claiming the works were obtained by a secret collector, the Times said.

Some of the works were then sold via Ann Freedman, former president of the illustrious gallery Knoedler & Company, which closed abruptly Wednesday after 165 years in the business.

Others were sold by independent dealer Julian Weissman, who had represented Motherwell when he was alive.

On Friday, London collector Pierre Lagrange sued Freedman and her gallery, claiming the “Untitled 1950” Pollock painting he bought in 2007 was in fact a forgery. Knoedler said there was no link between the suit and the gallery’s closing.

“It’s a sad day when a venerable gallery goes out of business when confronted with the fact that it sold its clients a $17 million fake painting rather than stand by their client,” Lagrange’s attorney Matthew Dontzin told the Times.

In his lawsuit, Lagrange said forensic analysis found that two paints used in the work were not invented until after Pollock died.

Experts have questioned the authenticity of at least 15 other works brought to market by Rosales over a two-decade period, according to the newspaper, adding that some collectors and dealers who purchased the pieces may have never known there were doubts about their authenticity.

A nonprofit created by Motherwell, the Dedalus Foundation, has said that seven paintings allegedly by the artist and supplied by Rosales were fakes. But there has been disagreement, with other experts arguing that some are genuine and noting that several have been shown at established art fairs.

Freedman and Weissman, speaking to the Times through their lawyers, said they still believed the works they sold were authentic and that they were not under investigation. Freedman even purchased and still owns a Motherwell, a Pollock and a Mark Rothko from Rosales for her own personal collection.

Rosales attorney Anastasios Sarikas told the newspaper that his client was indeed at the center of an inquiry by the Federal Bureau of Investigation and the United States Attorney for the Southern District of New York.

But he said Rosales “never intentionally or knowingly sold artwork she knew to be forged.”

The FBI began examining the paintings in 2009, according to the Times.

Freedman resigned from Knoedler that October after a 31-year tenure, though her lawyer Ronald Spencer said the investigation had not prompted her departure.