Lawyers for Representative Ilhan Omar accused the Justice Department on Oct. 16 of violating court-ordered safeguards during a search of her Washington home, CBS News reported.

In a letter reviewed by CBS News, Amy Jeffress and Joshua Matz demanded the immediate return of Ms. Omar’s property and preservation of all video and audio recordings of the search. Homeland Security Investigations agents seized her personal cellphone during Monday’s search as part of an investigation into possible fraud and false statements in her family’s immigration paperwork.

The lawyers said agents failed to notify Ms. Omar and the House of Representatives Office of General Counsel that they were executing the warrant, as the judge had required. They also said agents prevented her from contacting her lawyer for more than an hour after the search began, though she and her counsel were supposed to receive the warrant at the outset.

A Justice Department spokesperson disputed the accusations in a statement, calling the letter “riddled with false allegations and inaccuracies.”

“Our attorneys and law enforcement partners complied with all court orders and legal obligations, as they always do,” the spokesperson said. “Leaking a letter to the press right after sending it is not good faith. It is a publicity play.”

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The dispute concerns protections for legislative work under the Constitution’s speech and debate clause. Prosecutors first presented the warrant to a federal magistrate judge about a week before the search. The judge questioned why it contained no safeguards for Ms. Omar’s legislative privilege, prompting an extended exchange with prosecutors.

A 2007 ruling by the U.S. Court of Appeals for the District of Columbia Circuit, involving a search of the Rayburn House Office Building, held that a member of Congress must have an opportunity to screen seized material for legislative privilege before executive branch officials review it. Prosecutors initially argued that the ruling shouldn’t apply because agents would search Ms. Omar’s home rather than her congressional office, CBS News reported.

Some of Ms. Omar’s relatives received grand jury subpoenas days before the search. Her lawyers also challenged the timing of those steps so close to an election. Justice Department guidelines tell prosecutors and agents to avoid overt investigative actions that could affect an election’s outcome or advantage or disadvantage a candidate.

A cream ballot box with a ballot sticking out rests on the raised handle of a dark blue judge’s gavel against a yellow background.

“This vindictive, retributive, and politically motivated criminal investigation into one of the President’s chief congressional critics violates Representative Omar’s constitutional rights and threatens the separation of powers,” Ms. Jeffress and Mr. Matz wrote.

President Trump has repeatedly accused Ms. Omar of immigration fraud and made derogatory comments about her Somali heritage and religion. Her lawyers said there was no legitimate basis to suggest she had violated any law concerning her citizenship status. They said the search arose from a years-old conspiracy theory about conduct stretching back decades.

Homeland Security Secretary Markwayne Mullin publicly discussed the investigation on Friday, calling it a “strong case” in an interview with Andrew Kolvet on “The Charlie Kirk Show.” Such public discussion of an ongoing criminal investigation is unusual because of due process protections and grand jury secrecy rules.

Mr. Mullin said investigators had served multiple warrants on Monday with a judge’s authorization and expected to present their case to a grand jury.