Attorneys for Facebook and its founder, Mark Zuckerberg, say they have found evidence on a New York man's computer that proves he made up his claim that a contract he signed with Zuckerberg in 2003 makes him part owner of the world's largest social networking Web site.

Paul Ceglia sued Facebook in 2010, alleging that a contract he struck with Zuckerberg while he was still a student at Harvard University entitled him to half of the company. Although Zuckerberg reportedly signed a temporary contract with Ceglia that year after responding to a Craigslist helped-wanted ad for work on a street-mapping device called StreetFax, his lawyers argued that Facebook was never mentioned in that deal.

Ceglia claims the contract proves that he paid Zuckerberg $1,000 to work on the project, and then gave him another $1,000 payment after the future billionaire told him about his idea to create an online yearbook for college students. The contract, according to Ceglia, entitled him to half of the business, which he attempted to prove with a series of email exchanges in which he alleged he and Zuckerberg discussed the arrangement.

 In a court filing on Monday, Facebook's legal team - which Reuters reports characterized Ceglia as an "inveterate scam artist" -said the company found an authentic contract embedded in electronic data on Ceglia's personal computer. Facebook insists the document only mentions the StreetFax project and accused Ceglia of altering the original contract to insert references to Facebook.

"He 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," Facebook attorney Orin Snyder wrote, according to court filings.

Although Facebook's latest filings say Ceglia has given the company access to multiple computers, floppy disks and thousands of CDs, he has not provided them with any of the electronic documents he was ordered to produce. However, Ceglia's attorneys argue that Facebook has not given them 175 relevant emails from Zuckerberg's old Harvard account or a court-ordered sampling of his handwriting from 2003.

Lawyers for both parties are scheduled to appear before U.S. Magistrate Judge Leslie Foschio in Buffalo on Wednesday.

One thing's for sure: Ceglia's life will certainly change if a court sides with him. Facebook currently claims 750 million users across the globe and has an estimated net worth of $50 billion.