(NewsNation) — The House committee investigating the Jan. 6, 2021 riots at the Capitol have issued a subpoena for former President Donald Trump to answer questions about his role on and leading up to the day, claiming they believe he played a pivotal part in the riots.

In a letter to the former president, the nine-member committee demanded Trump’s testimony, saying it has “…assembled overwhelming evidence, including from dozens of your former appointees and staff, that you personally orchestrated and oversaw a multi-part effort to overturn the 2020 presidential election and to obstruct the peaceful transition of power.”

The deposition will be under oath, and the committee request Trump inform the committee if he intends to plead his Fifth Amendment Right against self-incrimination. 

“We recognize that a subpoena to a former president is a significant and historic action,” Chairman Bennie Thompson and Vice Chair Liz Cheney wrote in the letter to Trump. “We do not take this action lightly.”

It is unclear how Trump and his legal team will respond to the subpoena. He could comply or negotiate with the committee, announce he will defy the subpoena or ignore it altogether. He could also go to court and try to stop it.

The subpoena is the latest and most striking escalation in the House committee’s 15-month investigation of the deadly Jan. 6, 2021 insurrection, bringing members of the panel into direct conflict with the man they have investigated from afar through the testimony of aides, allies and associates.

The committee writes in its letter that it has assembled “overwhelming evidence” that Trump “personally orchestrated” an effort to overturn his own defeat in the 2020 election, including by spreading false allegations of widespread voter fraud, “attempting to corrupt” the Justice Department and by pressuring state officials, members of Congress and his own vice president to try to change the results.

But lawmakers say key details about what Trump was doing and saying during the siege remain unknown. According to the committee, the only person who can fill in the gaps is Trump himself.

The panel — comprised of seven Democrats and two Republicans — approved the subpoena for Trump in a surprise vote last week. Every member voted in support.

Citing President Theodore Roosevelt, the committee wrote “an ex-President is merely a citizen of the United States, like any other citizen. And it is his plain duty to try and help this committee or respond to its invitation.”

The committee requested his attendance at a deposition on or about Nov. 14.

The Associated Press Contributed to this report