Motherwell painting (top) claimed to be a forgery; Knoedler & Co Building (bottom). The gallery went out of business abruptly Nov 30.

Investigators have traced the source of the works to Glafira Rosales, who runs a Long Island gallery and often bragged of having a connection to a mystery collector with a large collection of postwar art by such masters as Mark Rothko and Richard Diebenkorn, according to The New York Times, which broke the story.

Ann Freedman, until 2009 the president of the prestigious gallery Knoedler & Co on the Upper East Side, was a conduit for the allegedly forged art.

Julian Weissman, an independent dealer who had worked for Knoedler in the 1980s and had represented Motherwell when he was alive, also reportedly sold some of the alleged fakes.

Both dealers insist they thought the paintings were genuine. Neither are reportedly under investigation, but Rosales has been notified she is a target, according to her lawyer, Anastasios Sarikas.

The Federal Bureau of Investigation and the United States Attorney for the Southern District of New York are handling the case.

Sarikas said his client had “never intentionally or knowingly sold artwork she knew to be forged,” according to the Times.

The Knoedler gallery shut its doors on Wednesday and has been sued by a London collector who bought one of the allegedly forged works, “Untitled 1950” by Pollock, for $17 million in 2007.

The collector’s forensic analysis found that two paints in the work had not been invented until after Pollock’s death, the suit claims.

At least 15 other works brought to market by Rosales over a period of nearly two decades have been questioned by experts, according to the Times.

The paintings were allegedly bought by the unnamed collector in the 1950s directly from the artists.

The works were later passed on to the son of the original collector, who reportedly lives in Mexico and Switzerland and has insisted on remaining anonymous.

For more details on the scandal check out The Times report.