Washington DC – A Republican member of the House select committee probing the January 6 siege of the US Capitol on Sunday wouldn’t rule out calling on fellow members of Congress to testify.

"I would support subpoenas to anyone that can shed light. ... If that’s the leader, that’s the leader," Rep. Adam Kinzinger, a Republican of Illinois, told ABC’s This Week.

He’d been asked if House Minority Leader Kevin McCarthy, a Republican of California, and Rep. Jim Jordan, a Republican of Ohio – who spoke to former President Donald Trump the day a throng of his supporters attacked the Capitol – should be subpoenaed.

"I want to know what the president was doing every moment of that day," Kinzinger said.

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He went on to say his questions include figuring out why it took hours for the National Guard to respond and whether Trump made calls about deploying them.

Kinzinger is one of just two Republicans on the panel, which began its investigation last week.

McCarthy dismissed the committee as a "sham" after House Majority Leader Nancy Pelosi, a Democrat of California, rejected two of his proposed appointments – Trump allies who have supported his unfounded claims that he really won the November presidential election.

McCarthy has also promised unspecified repercussions for Republicans who participate in the committee. Along with Kinzinger, Rep. Liz Cheney, a Republican of Wyoming, is on the panel.

"If anybody’s scared of this investigation, I ask you one question: What are you afraid of?" Kinzinger said Sunday. "Either you’re afraid of being discovered of having some culpability … or ... if you think it wasn’t a big deal, you should allow this to go forward."

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"It is essential, for history, for the American people, for truth, that we get to the bottom of this," he added. "Anybody with parts of that information, with inside knowledge, can probably expect to be talking to the committee."

The lawmaker shied away from saying Trump himself should be subpoenaed, explaining that information about his doings on January 6 could be gleaned from people around him that day.

"I would expect a significant number of subpoenas for a lot of people," Kinzinger said.