By Jacob Rosen,Melissa Quinn

Copyright cbsnews

Washington — Lindsey Halligan, one of President Trump’s former defense lawyers who then joined him in the White House, took over a key federal prosecutor’s office in Virginia on Monday following the departure of the U.S. attorney amid apparent pressure from the president.Halligan takes the helm of the U.S. Attorney’s Office for the Eastern District of Virginia as interim U.S. attorney after serving as a senior aide to Mr. Trump. Her temporary appointment comes days after Erik Siebert, who had been serving as the top prosecutor in the office, resigned amid concerns he would be forced out for failing to prosecute New York Attorney General Letitia James for alleged mortgage fraud. The president said he fired Siebert.Federal law allows Halligan to serve as interim U.S. attorney for only 120 days, unless federal judges on the U.S. district court in the region extend her appointment or she is confirmed by the Senate. The district court in the Eastern District of Virginia is known as the “rocket docket” because of how quickly cases move from filing to trial. It handles significant national security cases in part due to its proximity to Washington, D.C.In her role in the second Trump administration, Halligan was part of an effort by the White House to remove “improper ideology” from the Smithsonian Institution and its museums, education and research centers, and the National Zoo.Halligan, who worked as a special assistant to the president, signed a letter to Smithsonian Institution Secretary Lonnie Bunch last month informing him that the White House would be conducting an internal review of Smithsonian museums and exhibits “to ensure alignment with the President’s directive to celebrate American exceptionalism, remove divisive or partisan narratives, and restore confidence in our shared cultural institutions.”Before joining the White House and working for Mr. Trump, Halligan handled insurance claims at a law firm in Florida. She graduated from the University of Miami Law School in 2013 and was admitted to the Florida Bar in 2014. Halligan has never worked in a prosecutor’s office. A legal marketing website with Halligan’s resume, USattorneys.com, says that she interned at the Miami Public Defender’s Office and the Innocence Project. She was a member of Mr. Trump’s defense team in a case brought by former special counsel Jack Smith related to the president’s alleged mishandling of classified documents after the end of his first term. The president was charged with 40 federal counts after investigators discovered roughly 300 sensitive documents at his South Florida resort, Mar-a-Lago. Mr. Trump pleaded not guilty, and the case was dismissed last November after he won a second term in the White House.Mr. Trump announced Saturday that he would be nominating Halligan for U.S. attorney for the Eastern District of Virginia, writing on social media that she is “fair, smart and will provide desperately needed, JUSTICE FOR ALL!”The president had also publicly expressed frustration to Attorney General Pam Bondi for prosecutors’ lack of action against James, Democratic Sen. Adam Schiff of California and former FBI Director James Comey, some of the president’s most vocal critics.”We can’t delay any longer, it’s killing our reputation and credibility,” he wrote on Truth Social. “They impeached me twice, and indicted me (5 times!) OVER NOTHING. JUSTICE MUST BE SERVED, NOW!!!”The turmoil among the top ranks of the U.S. Attorney’s Office in Virginia came after Siebert, who served as the top prosecutor since January, told staff Friday he had resigned. Multiple sources told CBS News that federal prosecutors were concerned Siebert could be removed for failing to prosecute James for mortgage fraud.The federal judges in the Eastern District of Virginia had agreed in May to extend Siebert’s appointment.But Mr. Trump had expressed his displeasure with Siebert, saying Friday, “I want him out.” The president had nominated Siebert in May to serve as U.S. Attorney for the Eastern District of Virginia, and his nomination was awaiting a vote by the full Senate.The president criticized Siebert because he had the support of Virginia’s two Democratic senators, Tim Kaine and Mark Warner. A U.S. attorney nominee requires the backing of the two senators who represent the state to advance through the Senate Judiciary Committee. It seems unlikely Kaine and Warner would support Halligan’s nomination.Over the weekend, a conservative lawyer, Margaret “Maggie” Cleary, separately told staff in the U.S. Attorney’s Office for the Eastern District of Virginia that she had been named its top prosecutor in an acting capacity. CBS News has reached out to the White House and Justice Department for clarification. As of midday Monday, both Cleary’s name and Siebert’s name had appeared on separate court filings.