The investigation into whether Rep. Ilhan Omar, D-Minn., married her brother in an alleged immigration fraud scheme in 2009 began under former President Barack Obama in 2016, Fox News Digital has confirmed.

A U.S. Attorney in Minnesota, appointed by then-President Joe Biden, eventually shut down the probe in 2021, a source familiar with the matter told Fox News Digital.

Now, the issue has been thrust back into the spotlight as part of a new federal investigation into the Somali-born congresswoman, part of which centers on whether she or her father committed immigration fraud on her application to become a U.S. citizen.

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Sources previously told Fox News Digital that Omar's "real name" is Ilhan Nur Said Elmi. In a federal court document, she was called "Ilhan Omar Nur Said Elmi, a/k/a Ilhan Omar."

In 2009, Omar, then a U.S. citizen, legally married a man with that surname, Ahmed Nur Said Elmi. The pair officially split in 2017.

The New York Times first reported that Obama's FBI and Department of Homeland Security (DHS) began the probe in the summer of 2016, and that officials "found some evidence that [the marriage] was fraudulent." The Times reported that the investigation concluded when officials decided the potential felony crime was past the statute of limitations.

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Despite his own administration's investigation into Omar at the time she was running for the Minnesota House, Obama condemned the renewed probe, which included a Homeland Security Investigations (HSI) raid on her Washington, D.C. home on Oct. 12. Federal authorities confiscated her passport, personal phone and computer in the raid.

"It is a basic principle of American democracy that the government can’t selectively target individuals simply because of their political beliefs or what they say," Obama wrote in an X post after the raid earlier this month. "But that’s exactly what the Trump Administration is doing to Congresswoman Ilhan Omar of Minnesota."

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Obama claimed the Trump administration was targeting Omar because she is a vocal critic of the current president.

"Think about that," Obama said in the post. "The full weight of the federal government is being brought down on a law-abiding elected official because she has dared to criticize the president."

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Omar has frequently called the allegations that she married her brother a conspiracy theory promulgated by the political right, including in a statement to Fox News Digital regarding the new investigation last week.

"Rep. Omar has repeatedly and unequivocally denied this baseless, disgusting conspiracy theory," an Omar spokesperson said. "This is a desperate political smear designed to distract from Trump’s failed presidency and two years of Republican failure in Congress. And it’s disgraceful that the media continues to give this lie oxygen."

The same spokesperson did not immediately respond to a Thursday morning request for comment.

Fox News Digital's Andrew Mark Miller contributed to this report.