A naturalised American man of Indian origin became the first person to lose his citizenship in the United States under the Donald Trump administration’s efforts curb immigration to the country. The government has been examining thousands of people who investigators believe may have been erroneously granted citizenship, AFP reported on Tuesday.

Baljinder Singh, 43, from the town of Carteret in New Jersey, became a naturalised US citizen in 2006 after marrying an American woman. The US Justice Department told a federal judge in New Jersey that Singh arrived in the country in 1991 without travel documents or proof of identity and told authorities that his name was Davinder Singh. He did not appear for court hearings and was ordered to be deported in January 1992. A month later, he filed for asylum under the name Baljinder Sing but abandoned the attempt after getting married.

Singh should have been caught in 2006 but was naturalised after the government bungled up a fingerprint check, The Washington Times reported. His fingerprints were contained in a paper file, and investigators had checked only the electronic system, thereby failing to catch him, the US Justice Department said.

“The defendant exploited our immigration system and unlawfully secured the ultimate immigration benefit of naturalisation, which undermines both the nation’s security and our lawful immigration system,” Chad Readler, the acting assistant attorney general in the department’s Civil Division, said in court.

On January 5, the judge revoked Singh’s citizenship. His status is now that of a lawful permanent resident, which means he can be deported to India.

“I hope this case, and those to follow, sends a loud message that attempting to fraudulently obtain US citizenship will not be tolerated,” said US Citizenship and Immigration Services Director Francis Cissna, who was appointed by Trump.

The proceedings against Singh were part of Operation Janus, which is a programme of the US Department of Homeland Security against fraudulent immigration.