Denver Mayor Mike Johnston will soon be on his way to Washington D.C. to testify before the U.S House Oversight and Government Reform Committee to explain the city’s “sanctuary jurisdiction” policies.

Kentucky Rep. James Comer, the Republican who chairs the House Oversight Committee, confronted four Democratic sanctuary city mayors on Wednesday over their refusal to fully cooperate with Immigration and Customs Enforcement.

Denver Mayor Mike Johnston is already in Washington, D.C., preparing to testify before the U.S. House Oversight and Government Reform Committee that is investigating “sanctuary" jurisdictions.