In a lawsuit filed on Friday, nine art collectors claimed that the Keith Haring Foundation cost them at least $40 million by labeling about 90 paintings as fakes.

Artworks by the late Haring were not fully examined by the foundation, claims the suit filed in U.S. District Court in Manhattan. The collectors allege that the foundation operated "in secret," and that they made conslusions about authenticity with "little or no explanation, and often without ever physically inspecting the works."

Prior to his death of AIDS in 1990, Haring formed the foundation which disbanded in 2012 to avoid litigation, according to the suit.

A "Haring Miami" exhibition planned last March in Florida with works from the plaintiffs was cancelled after the foundation sued the organizers, claiming that most of the 200 artworks on display were counterfeits and that they would be worth $40 million only if they were truly by Haring.

"Putting all these cheap Haring fakes into the market will depress the market and irreparably destroy the value of the authentic art and the reputation of the artist and the artwork," claimed the foundation's lawyers. The foundation said one of their directors viewed the artworks and was "shocked at the blatant fraud involved."

The collectors say the artworks were purchased directly from two of Haring's friends. Attempts to get the foundation to review them "proved fruitless," according to the suit. They are suing for $40 million in damages for lost sales.