Rep. Bennie Thompson, the top Democrat on the committee, lambasted the second Trump administration, saying it's "out of control" and has been "running roughshod over Americans' rights, killing U.S. citizens and threatening our very democracy."

"The disease rotting the Trump administration from the inside out started at the top and has infected every part of the executive branch," he said. "Nowhere is that more evident than at the Department of Homeland Security."

Thompson, of Mississippi, accused the Trump administration of deliberately thwarting an investigation into the killing of Renee Good in Minnesota last month. He said the blocking of a probe into the government's use of force against an American citizen is a sign of a dictatorship, not a democracy.

"Every American should be outraged," he said.

Thompson also criticized DHS — and Lyons, specifically — for rebuffing invitations to testify before lawmakers. That changed, however, after the shooting death of Alex Pretti last month. 

"This is part of a pattern of the Trump administration's refusal to comply with regular congressional oversight," he said.

Thompson denounced Homeland Security Secretary Kristi Noem and accused her of gaslighting the public by making up a "demonstrably false story" about Pretti. He said she has "enriched herself, abused the power of her office, obstructed congressional oversight and violated her oath to the Constitution."

"Secretary Noem's Department of Homeland Security has the blood of American citizens on its hands, but she takes no responsibility for anything," Thompson said. 

He said Noem is a "liar" who should no longer hold her role.