The lawsuit filed by a man who says Facebook founder Mark Zuckerburg owes him an 84 percent stake in the company is based on forged documents, according to Zuckerburg's lawyers, who now say they have a "smoking gun" that proves it. New York state resident Paul Ceglia sued Facebook last year, alleging that Zuckerberg signed a contract with him in 2003, entitling him to part ownership of the company. The contract's authenticity is hotly disputed, and Reuters reports that in a court filing Thursday, attorneys for Facebook say they've uncovered documents on Ceglia's computers that prove he's an "inveterate scam artist."

Facebook attorneys have not yet revealed what the smoking gun is exactly (nothing yet on The Smoking Gun either), because they need a judge's permission to make the gun public. In the court filing, they write that Ceglia "does not want the public to know what was discovered on his computers, 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."

Both sides agree the two men had contact when Zuckerberg was at Harvard. But Zuckerberg claims their agreement applied solely to a Ceglia project called StreetFax, and his attorneys say they've recovered emails from Zuckerberg's Harvard email account that support this claim. Ceglia, for his part, says he found the contract after looking through old papers when Andrew Cuomo filed a lawsuit against him (claiming he defrauded customers of his wood-pellet fuel company). He's currently living in Ireland, according to court documents obtained by the Post.