A federal judge last week stripped an Indian national of his U.S. citizenship in what officials described as the first case to grow out of an Obama-era federal investigation that exposed rampant fraud among citizenship applicants.

Federal prosecutors had sought the denaturalization of Baljinder Singh in September, arguing that the 43-year-old native of India had fraudulently obtained his citizenship.

According to prosecutors, Singh first entered the U.S. under a false name in 1991 and subsequently faced deportation, but he failed to disclose that information in his 2004 citizenship application.

Under U.S. law, naturalization can be revoked if it was obtained through fraud.

On January 5, Federal Judge Stanley Chesler of the District of New Jersey, where Singh lives, granted the government's request to revoke Singh's citizenship, reverting his status to a green card holder and potentially subjecting him to deportation, the Justice Department announced Tuesday.

The judge's order came after Singh failed to respond to the Justice Department's denaturalization complaint and subsequent request for a summary judgment, according to court documents.

Singh could not be immediately reached.

Operation Janus

The Justice Department said the case was the first to result from Operation Janus, a Department of Homeland Security probe that identified 315,000 immigrants whose fingerprints were missing from government databases. The immigrants faced deportation or were criminal fugitives and "some may have sought to circumvent criminal record and other background checks in the naturalization process," the Department said.

A 2016 audit by the Homeland Security Department's inspector general first disclosed the missing fingerprint data and found that the U.S. Citizenship and Immigration Services had mistakenly granted citizenship to at least 858 immigrants facing deportation.

The immigrants used different names and birth dates to apply for citizenship, according to the audit.

The inspector general criticized Immigration and Customs Enforcement for failing to investigate the apparently fraudulently naturalized citizens but said the agency was "now taking steps to increase the number of cases to be investigated, particularly those who hold positions of public trust and who have security clearances."

The pace of the investigations appears to have picked up over the past year, with the U.S. Citizenship and Immigration Services reporting a "growing body of cases" to the Justice Department.

Last year, the Justice Department filed 25 civil denaturalization cases and 57 criminal cases, according to a department spokesman.

The U.S. immigration agency said it plans to refer about 1,600 additional cases uncovered by Operation Janus for possible denaturalization.

"I hope this case, and those to follow, send a loud message that attempting to fraudulently obtain U.S. citizenship will not be tolerated," USCIS Director Francis Cissna said in a statement. "Our nation's citizens deserve nothing less."

Denaturalization

Singh faces certain deportation, according to Amanda Frost, a professor at the American University Washington School of Law.

"Now that they've denaturalized him, their next move is to take away his green card and deport him," Frost said. "If they don't do that, I'm not sure what the purpose of this entire proceeding was."

Chad Readler, the acting head of the Justice Department's Civil Division, said Singh had "exploited our immigration system and unlawfully secured the ultimate immigration benefit of naturalization."

"The Justice Department will continue to use every tool to protect the integrity of our nation's immigration system, including the use of civil denaturalization," Readler added.

The government is also seeking the denaturalization of two Pakistani nationals who are accused of concealing deportation orders from immigration officials.

In recent years, the number of denaturalization cases has been in the dozens, according to Frost. But Operation Janus suggests that the government is "putting more resources into this than it did before," Frost said.

The U.S. government used denaturalization throughout the first half of the 20th century to take away the citizenship of people suspected of Communist sympathies or fighting in foreign wars.

But a landmark Supreme Court decision in 1967, Afroyim v. Rusk, put an end to the practice, said Frost, who researches denaturalization.

"The court made it clear that denaturalization was limited," Frost said.

Last year, the Supreme Court handed down a decision in another denaturalization case, barring the government from denaturalizing citizens for making "non-material" false statements on their citizenship applications.

"It served to remind the government that there are many constitutional protections in this area and that denaturalization must be done carefully," she said.