A New York businessman who shocked the world with claims that he was the rightful owner of half of Facebook, only to be charged with criminal fraud and then flee, has been on the run for so long that the judge in the case is demanding answers from federal authorities—which so far, they are not providing.

But investigators insist the trail of Paul Ceglia has not gone cold, even as they appeal to the public for help.

Ceglia, a former heating fuel dealer from upstate New York, came out of nowhere in 2010 to claim he had a contract signed by Facebook founder and CEO Mark Zuckerberg to prove the ownership stake. But after investigators from Facebook convinced a federal judge that the contract was a fake, prosecutors followed up with criminal fraud charges.

Then last year while awaiting trial, Ceglia vanished, having briefly fooled authorities by rigging his home monitoring device Ferris Buehler-style to make it look like he was still living under house arrest. Ceglia's wife, two young children, and the family dog have gone missing as well.

But a deputy United States Marshal working the case says the investigation is still active, even though prosecutors missed a court-imposed deadline earlier this month for a progress report on the manhunt.

"I can't get into all the details of the investigation, but we are continuing to work on all the leads that have come in, both domestic and international," Deputy U.S. Marshal Scott Baryza tells American Greed.

After Ceglia skipped bail in March 2015, United States District Judge Vernon Broderick in Manhattan ordered the U.S. Attorney's office to update him every four months on the progress of the search. But in a filing on June 9, the judge noted that the government has not provided an update since December.

In that letter, prosecutors only say that Ceglia remains a fugitive, and that investigators are "using a variety of law enforcement tools and following up on leads from those responding to requests for information."

In his most recent order, Judge Broderick told prosecutors to file another update no later than June 24, but they have not yet done so.

If authorities have narrowed down their search for Ceglia, they are not saying much.

"We know he's had ties in the past with Florida, Texas, California, and the state of Washington," Baryza says.

But with more than a year on the run, Ceglia has had time to travel farther than that.

"We know his family is from Ireland, so there's also the possibility that he could be outside the U.S. too," Baryza says.

In fact, Ceglia has dual citizenship in Ireland, though he surrendered both his U.S. and Irish passports following his arrest in 2012.

Perhaps it should come as little surprise that Ceglia, 42, is proving to be a slippery character. His high school classmates in Wellsville, New York, voted him "most corrupt," according to the 1991 school yearbook.

"A lot of his high school friends were saying he always had some kind of a scheme going or some kind of a make-money-quick business idea, and that was kind of his M.O.," says John Anderson, regional editor at the Wellsville Daily Reporter.

The scheme to claim half ownership of Facebook—a stake that would have been worth $11.5 billion in 2010 and more than ten times that today—was the wildest of all.

Ceglia claimed that he had hired Zuckerberg to write some software for him while Zuckerberg was still a student at Harvard. Ceglia said he later agreed to allow Zuckerberg to use the software as the source code for the new social network he was developing—a network that would become Facebook—in exchange for half interest.

Zuckerberg has acknowledged that he worked with Ceglia, but he and Facebook have denied everything else. They hired forensic experts to show the Ceglia had altered the actual contract the two had signed for the software job to make it look like Zuckerberg was signing over half interest in Facebook.

A federal judge dismissed Ceglia's civil claims, and a federal grand jury indicted him for mail fraud and wire fraud.

He could face up to 40 years in prison if convicted, but first authorities have to find him, and they are asking for the public's help.

"It's really any information," Baryza says. "You know, the public may think it's a small piece of insignificant information but as the case goes on as a whole it could be a significant piece in finding him."

You can e-mail the U.S. Marshal Service at usmswanted@usdoj.gov, call them at (800) 336-0102, or send an anonymous text to "TIP411" (847411) with "USS Ceglia" as the first line.

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