Authorities from Manhattan federal court are investigating whether paintings and drawings sold by a 165-year-old art gallery, Knoedler & Co, which included purported works by Jackson Pollock and other Modernist masters, are forgeries.

The complaint against the gallery was filed by London collector Pierre Lagrange who is also the co-founder of GLG Partners Inc.

According to Lagrange, an Untitled 1950 Pollock painting that he bought from the Manhattan gallery back in 2007 was a forgery. In 2010, when he tried to resell the art-piece, both Christie's and Sotheby's expressed concerns about the authenticity of the paintings.

Following this, Lagrange reportedly hired a consulting company who finally confirmed that the painting was a fake.

Bloomberg reported that Ann Freedman, former director of the gallery, who left Knoedler two years ago and now runs FreedmanArt gallery, didn't return calls or emails seeking comment on Lagrange's claims.

Earlier this week, the Knoedler gallery abruptly closed after years of business. A statement mentioned on the Web site reads: It is with profound regret that the owners of Knoedler Gallery announce its closing, effective November 30, 2011. This was a business decision made after careful consideration over the course of an extended period of time. Gallery staffs are assisting with an orderly winding down of Knoedler Gallery.