Federal authorities raided the Washington, D.C.-area home of Rep. Ilhan Omar on Monday morning. The Department of Justice confirmed the action as part of an ongoing criminal fraud investigation into immigration paperwork filed by the Minnesota Democrat's father. Fox News first reported the raid, citing a person familiar with the situation, before the DOJ acknowledged the matter to CNBC.

Homeland Security Investigations, a division of the Department of Homeland Security, conducted the search. The Department of Homeland Security declined to comment on the raid. A source familiar with the non-public investigation told CNBC that the probe is complex and has been active for years. The source spoke on condition of anonymity.

In a statement to CNBC, the Department of Justice said that Homeland Security Investigations carried out a judicially authorized search warrant in the Washington, D.C., area that was secured by the department. The statement added that this enforcement action is part of an ongoing federal investigation.

Omar, 44, was born in Somalia and brought to the United States as a child. She became a U.S. citizen in 2000 at age 17. Elected in November 2018, she represents Minnesota's 5th District, which includes all of Minneapolis. She and Rep. Rashida Tlaib, D-Mich., were the first two Muslim women elected to Congress.

The raid occurs less than a month before the November midterm elections. Omar is seeking another term in her district, where Republican John Nagel is her opponent. The Cook Political Report with Amy Walter rates the race "solid Democrat." The general election is scheduled for Nov. 3.

The Department of Justice has a policy regarding federal investigations and prosecutions near elections. The policy discourages beginning investigations, taking investigative steps, bringing charges, or making public statements intended to affect an election or give a candidate an advantage or disadvantage. A person familiar with the raid told CNBC on Monday that the DOJ does not consider the action a violation of that policy because it was not meant to be public.

Omar has faced criticism from President Donald Trump. She heckled him during his State of the Union address on Feb. 24, following aggressive immigration enforcement actions in Minneapolis by federal authorities. CNBC has requested comment from Omar's office.