The presidential call log for Jan. 6, displayed at a hearing by the House select committee investigating the Jan. 6 attack on the U.S. Capitol, Thursday, July 21, 2022, on Capitol Hill in Washington. House Select Committee via AP, file

WASHINGTON — Working at an urgent pace, the House committee investigating Jan. 6 has managed in 15 months to collect a staggering trove of material that includes transcripts of more than 1,000 interviews and millions of other documents.

Soon, the panel’s evidence about an unprecedented attack on democracy – most of which the public has never seen – will need a safe home.

The seven Democrats and two Republicans on the panel have said that their probe of the 2021 insurrection is for history, not only for current concern, and to ensure that nothing like it ever happens again. But Republicans allied with former President Donald Trump who are hostile to the investigation could take the congressional majority in the November elections, potentially making it harder for the committee to protect its documents and transcripts if they are not already made public.

Members and staff have begun internal discussions about how their investigation will be preserved once the committee is shut down early next year, with no clear resolution yet on what will be made public and how, according to people familiar with those talks.

The committee’s final report is likely in December, but it’s uncertain how much of the source material will accompany it – such as emails and text exchanges turned over by witnesses, internal White House memos, calendars, handwritten notes, surveillance video, law enforcement radio transmissions, taped interviews and more.

There are volumes of documents and testimony from Trump allies and former aides about his actions before and during the Capitol assault, including internal White House logs and thousands of texts turned over by his chief of staff Mark Meadows. Also included: a million and a half pages of documents turned over by the Secret Service, some of which will be discussed at a hearing Thursday.

“It will require some careful planning in the months ahead” to ensure the public and law enforcement have access to a detailed record of the committee’s work, says lawyer Susanne Sachsman Grooms, a former Democratic investigator for the House Oversight and Reform Committee who worked on both of Trump’s impeachments.

Grooms noted that the Democratic chairman of the committee, Mississippi Rep. Bennie Thompson, currently has control over all of the information obtained during the investigation but must tread carefully.

“Like any investigative committee, I’m sure that the chair will also be balancing his interest in creating a historical, public record with any commitments that the committee has made during its investigation to protect sensitive information, such as the identities of whistleblowers, from exposure and potential retaliation,” Grooms said.

The panel is under pressure because it will expire when the current Congress ends at the beginning of next year, or 30 days after it releases its final report. And the investigation has amassed an unusually large amount of material, as hundreds of witnesses have turned over relevant documents.

While some of the evidence has been aired, and more is expected in the hearing this week, the committee has released only snippets of most interviews and very few of the documents it possesses.

In one of eight investigative hearings last summer, Maryland Rep. Jamie Raskin, a Democratic member of the panel, stressed that the investigation was continuing and “we have only shown a small fraction of what we have found.” He said he looked forward to “the public release of more of our findings later.”

Indeed, the inquiry isn’t over – the panel is still talking to witnesses, gathering materials and pulling investigative threads. Further complicating matters, the Department of Justice is conducting its own investigations and prosecutions related to Jan. 6 and has asked the panel for interview transcripts and other materials.

Preserving evidence is just one of many remaining questions about what is next for the investigation into the insurrection, and it could be a key issue if Republicans take the majority and start their own Jan. 6 probes, potentially with the ability to subpoena the committee’s documents.

Republicans have criticized the Democrat-led probe as partisan and a political attack on Trump, who encouraged his supporters to “fight like hell” in a speech the morning of the assault, just before hundreds of them pushed past police and broke into the Capitol. Most Republicans have stuck by the former president, and some lawmakers have echoed his false claims of widespread election fraud.

A House-passed resolution forming the committee last year established the panel’s rules and also included directions for the “disposition of records,” giving the speaker of the House the power to designate a committee to oversee the materials. But it’s unclear which committee that would be.

The Jan. 6 panel could also work with the National Archives, Library of Congress or Government Printing Office to create a space to save the materials for decades to come. Professional contractors paid by the committee have already helped the panel organize some of the materials as part of the investigation.

Also unsettled is whether the committee will transfer specific records to the Justice Department – or just make them public for all to see. Though most of the panel’s materials are unclassified, it could transfer some unredacted documents to federal investigators. So far, though, the committee hasn’t sent any of the information that the department has requested.

With a little more than two months to go, committee members aren’t yet saying what they will do. But they say they are confident their work will last.

“We’re going to make sure that everything is taken care of,” said Rep. Zoe Lofgren, a California Democrat who sits on the panel.