Hassan, who is expected to become chairwoman of the Senate Homeland Security and Governmental Affairs Committee when Democrats assume control of the chamber in January, issued the warning in a letter sent Tuesday.

The New Hampshire senator said she intends to use the committee’s full investigative powers, including compulsory legal measures, to examine allegations of financial misconduct and questionable contracting practices within the Department of Homeland Security.

She emphasized that any missing or destroyed records would raise additional questions about accountability and transparency.

The latest development comes as federal prosecutors investigate contracting activities at the Department of Homeland Security during the first year of President Donald Trump’s second administration.

According to sources familiar with the investigation, Justice Department officials are examining Lewandowski’s conduct following a referral from DHS Inspector General Joseph Cuffari.

Lewandowski, a longtime political ally of Trump, previously served as a senior adviser to former Homeland Security Secretary Kristi Noem, reportedly exercising considerable influence over departmental operations.

The investigation is understood to be in its preliminary stages, with prosecutors reviewing allegations concerning the handling of government contracts and possible financial misconduct.

However, Lewandowski has repeatedly denied any wrongdoing.

His attorney previously stated that the former adviser had not been contacted by the Justice Department regarding the investigation and maintained that he had acted appropriately while serving the country in a voluntary capacity.

Hassan’s latest letter follows an earlier request in June seeking documents and other records relating to Lewandowski’s activities at DHS.

At the time, Lewandowski’s legal representatives argued that he was under no legal obligation to comply with the request while Democrats remained in the Senate minority.

However, the political landscape has since changed following the 2026 midterm elections, which saw Democrats secure control of both chambers of Congress.

With Hassan preparing to lead the Homeland Security and Governmental Affairs Committee, she is expected to gain expanded authority to demand documents, summon witnesses and conduct hearings into government activities.

The senator has also indicated that she intends to question Lewandowski under oath about his conduct at the agency.

She has requested that he provide the outstanding documents and confirm the preservation of relevant records by November 23.

The investigation could intensify scrutiny of contracting procedures within the Department of Homeland Security, particularly allegations that political influence may have affected decisions involving public funds.

Congressional investigators are expected to examine whether government contracts were handled appropriately and whether federal ethics and recordkeeping requirements were followed.

The inquiry could also raise broader questions about oversight of political appointees and advisers holding influential positions within federal agencies.

Lewandowski’s lawyer did not respond to ABC News’ latest request for comment regarding Hassan’s letter.

The renewed investigation comes as Democrats prepare to take control of Congress and increase oversight of the Trump administration.

Hassan’s warning signals that potential misconduct within federal agencies could become a major focus of congressional investigations when the new legislative session begins in January 2027.

For Lewandowski, the immediate concern is ensuring that all relevant documents and communications from his tenure at DHS remain available for examination.

While the Justice Department investigation and congressional scrutiny continue, no criminal wrongdoing has been established against him.

The outcome of the inquiries could have wider implications for government transparency, federal contracting practices and accountability within the Trump administration.