Facebook says it has uncovered smoking gun evidence that a contract at the heart of a lawsuit against the company and its founder Mark Zuckerberg is fraudulent, according to a Facebook court filing.

New York state resident Paul Ceglia sued Facebook in July 2010, alleging that a contract he struck with Facebook co-founder Mark Zuckerberg in 2003 entitled him to half the company.

Facebook, the world's No. 1 Internet social network with more than 500 million users, has said that Ceglia's contract is a forgery and has characterized Ceglia as an inveterate scam artist.

In a court filing on Thursday, attorneys for Facebook said they had uncovered documents on Ceglia's computers that undermine his claims. Facebook did not reveal the documents, but has asked a U.S. judge for permission to make them public.

does not want the public to know what was discovered on his computers, attorneys for Facebook wrote, because it includes smoking-gun documents that conclusively establish that he fabricated the purported contract and that this entire lawsuit is a fraud and a lie.

An attorney for Ceglia did not immediately respond to a request for comment.

The case is Ceglia v. Zuckerberg et al, U.S. District Court, Western District of New York, No. 10-00569.

(Reporting by Dan Levine, editing by Gerald E. McCormick)

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