The House select committee investigating the Capitol attack has amassed a huge trove of evidence as it seeks to connect the Trump White House to the 6 January insurrection, three months after it issued its first subpoenas to the former president’s most senior administration officials.

The select committee revealed on Monday that members had reviewed thousands of documents turned over by Trump’s former White House chief of staff Mark Meadows, which showed the White House played a far more substantial role in overturning the 2020 election than previously known.

But those communications and other documents that Meadows turned over represent just a small sample of evidence potentially incriminating the Trump White House collected since September.

The committee expects this week to depose more top aides, including the Trump justice department official Jeffrey Clark, from whom they hope to learn more about Trump’s efforts to reinstall himself as president – even if Clark invokes his fifth amendment right against self-incrimination.

That hope stems from the fact that Clark agreed to appear for a deposition just moments before the select committee would have recommended his prosecution for defying a subpoena – a circumstance that members believe means he will cooperate.

Bennie Thompson, the panel chair, said on Monday that after depositions this week, the panel was on track to interview more than 300 witnesses and add to the more than 30,000 documents already turned over.

The select committee also obtained about 6,000 documents from Meadows as part of a delicate cooperation agreement requiring the production of non-privileged material, before Meadows abruptly broke off the deal last week.

Part of the reason Meadows ended the cooperation deal was that he had learned from his personal cellphone carrier – believed to be Verizon – that the committee had started pursuing his call detail records, his attorney George Terwilliger said in a letter.

The select committee has in recent weeks issued subpoenas for the call detail records of several hundred phone numbers, which typically reveal the date, time, duration and target numbers of calls, according to a source close to the investigation.

Such records are expected to prove a boon for the inquiry, the source said, since it enables House investigators to map a pattern of which phone numbers were being dialed, and to connect key phone numbers to others on 6 January and the days and weeks before.

The release of Meadows’ cellphone records could come around the same time the committee potentially gains access to the several hundred pages of documents from the Trump White House held by the National Archives.

The select committee is on track to obtain those records, which Trump has claimed are subject to executive privilege and cannot be given to Congress, after the US court of appeals for the District of Columbia last week upheld a lower court ruling approving their release.

In a unanimous decision, the federal appeals court denied Trump’s request for an injunction, saying in a blunt ruling that in a dispute between a current and former president over whether to release White House records, the sitting president’s view must prevail.

Those records, so aggressively defended by Trump, the select committee believes, might help members make the case that the former president interfered with Biden’s certification with corrupt intent, a potential crime, the source said.

In the cache of communications Meadows furnished, the select committee said, were text messages he received from Republican members of Congress, in the days before the Capitol attack and on 6 January, from Fox News hosts and Donald Trump’s eldest son, Donald Jr.

Among the messages to Meadows that the committee disclosed was one from an unidentified Republican lawmaker, who apologized to Meadows after the Capitol attack for not succeeding in stopping Joe Biden from being pronounced president.

“Yesterday was a terrible day,” the text message from the Republican lawmaker read, referring to the Capitol attack, before saying of the attempt to prevent Biden’s certification: “We tried everything we could in our objection to the 6 states. I’m sorry nothing worked.”