Facebook fired back Thursday at Paul Ceglia, the man who claims half-ownership in Facebook, filing court documents alleging that the purported contract and e-mails with founder Mark Zuckerberg are fakes and that Ceglia engaged in widespread land fraud in Florida.

Zuckerberg also personally filed an affidavit, confirming that he did sign a contract to do work for Ceglia, but denying that it anything to do with Facebook.

“I did not enter into any agreement, written or otherwise, with StreetFax, Ceglia, or anyone affiliated with Ceglia concerning Facebook or any related social networking site,” Zuckerberg said in a sworn affidivat. “I did not write or receive any of the alleged e-mails quoted in the Amended Complaint.”

Ceglia filed suit last summer, alleging that in addition to hiring Zuckerberg to work on his StreetFax company he had fronted Zuckerberg $2,000 in exchange for half of Facebook when Zuckerberg was a young Harvard computer science student at Facebook. Ceglia claimed he’d forgotten about his investment and that he was due more than half of the company, now valued at more than $60 billion.

Ceglia subsequently produced a scanned copy of a contract, allegedly signed by Zuckerberg, giving Ceglia 50 percent of a social network called The Page Book. He also produced alleged e-mails to Zuckerberg’s Harvard account that showed Zuckerberg acknowledging Ceglia’s ownership.

The new legal filings ask the New York federal court overseeing the case to speed up proceedings so Facebook and Zuckerberg can see the original of the contract. The company also hired experts who expressed deep skepticism about the legitimacy of the e-mails and contract.

Frank Romano, a document expert and emeritus professor at the Rochester Institute of Technology, said that the two-page contract had different spacing and fonts, and had been printed on two printers at different times.

“It is my conclusion that Page 1 of Exhibit B (the contract) is an amateurish forgery,” Romano said in a sworn affidavit.

A forensic expert also examined the e-mail archives at Harvard and found that none of the e-mails introduced by Ceglia were among the 175 e-mails between Zuckerberg and Ceglia’s company that are in the archive. However, the examiner did unearth several e-mails from Ceglia apologizing to Zuckerberg for not having paid him for the programming work Zuckerberg did for Ceglia’s StreetFax.com company.

A private investigator for Kroll also filed an affidavit, alleging that Ceglia had defrauded numerous Florida residents through property sales on eBay, involving land that could not be developed. Kroll alleges Ceglia gave buyers altered paperwork to convince the buyers the land could be built upon.

The Ceglia suit adds to the legal complications surrounding the founding of Facebook. Two Harvard twins, Tyler and Cameron Winkelvoss, also sued Zuckerberg, alleging he stole their ideas and defrauded them after initially agreeing to do programming work for their social networking site. The duo settled with Facebook for about $46 million in stock and cash — but subsequently went to court to undo the settlement on the grounds that Facebook misled them about the value of the shares.

That attempt to re-open the case has fared poorly in the courts, but the twins are vowing to appeal their case to the Supreme Court.

Photo: Scott Beale/Laughing Squid