Senator Richard Blumenthal said he would open a perjury investigation into the ousted homeland security secretary Kristi Noem after alleging she lied to Congress about the hidden influence her senior adviser Corey Lewandowski had over the agency’s contracts.

Blumenthal, a Connecticut Democrat and ranking member on the Senate’s permanent subcommittee on investigations, said Thursday he would push the panel to look into whether Noem committed perjury at a hearing this week, when she flatly denied Lewandowski had played any role in approving Department of Homeland Security (DHS) spending. Blumenthal said Democrats had evidence to prove otherwise.

“Her firing doesn’t absolve her or relieve her of potential liability for perjury,” he said. “We are going to pursue an investigation of the evidence that she lied, because it relates to corruption in the administration.”