The House panel investigating the US Capitol insurrection on 6 January has requested an interview and documents from Scott Perry, the Republican representative of Pennsylvania, marking the first time the committee has publicly sought to interview a sitting member of Congress.

The latest request launches a new phase for the lawmakers on the committee, who have so far resisted reaching out to one of their own as they investigate the insurrection by former president Donald Trump’s supporters and his efforts to overturn the election.

Perry and other congressional Republicans met Trump before the attack and strategised about how they could block the results at the 6 January electoral count.

In a letter to Perry, Mississippi Rep Bennie Thompson, the Democratic chairman of the panel, said the panel had received evidence from multiple witnesses, including the then-acting attorney general, Jeffrey Rosen, and the then-acting deputy attorney general, Richard Donoghue, that Perry had “an important role” in efforts to install Justice Department official Jeffrey Clark as acting attorney general.

The letter requests an interview with Perry, who pushed the Justice Department to overturn the election and met Trump ahead of the violent attack, according to investigators. The panel also asked for any documents and correspondence between Perry and Trump, his legal team or anyone involved in the planning of the events of 6 January.

A request for comment left with Perry’s office was not immediately returned.

The lawmaker representing Pennsylvania’s 10th District was cited more than 50 times in a Senate Judiciary report released in October outlining how Trump’s effort to overturn his 2020 election defeat brought the Justice Department to the brink of chaos and prompted top officials there and at the White House to threaten to resign.

Perry, who has continuously disputed the validity of Joe Biden’s victory in Pennsylvania, has said he obliged Trump’s request for an introduction to Clark, then an assistant attorney general whom Perry knew from unrelated legislative matters. The three men went on to discuss their shared concerns about the election, Perry has said.

The Justice Department found no evidence of widespread fraud in Pennsylvania or any other state, and senior Justice officials dismissed Perry’s claims

The recent Senate report outlined a call Perry made to Donoghue last December to say the department was failing to do its job with respect to the elections. Perry encouraged Donoghue to elicit Clark’s help because he’s “the kind of guy who could really get in there and do something about this”, the report said.

Perry had previously said his “official communications” with Justice Department officials were consistent with the law.

The letter sent on Monday night is the first time the panel has publicly released a request to a fellow member of Congress as it investigates Trump’s communications with his Republican allies. But the panel notably did not subpoena Perry, as it has other witnesses close to Trump whom lawmakers believe have relevant information.

In his letter to Perry, Thompson added that the panel “has tremendous respect for the prerogatives of Congress and the privacy of its members. At the same time, we have a solemn responsibility to investigate fully all of these facts and circumstances.”

The panel voted in November to hold Clark in contempt after he showed up for a deposition yet declined to answer questions. But Thompson has said he will hold off pursuing the charges and allow Clark to attend another deposition and try again. Clark’s lawyer has said Clark intends to assert his fifth amendment right not to incriminate himself, but the deposition has been repeatedly postponed as Clark has dealt with an unidentified medical condition.

The panel has already interviewed about 300 people as it seeks to create a comprehensive record of the attack and the events leading up to it.

Trump at the time was pushing false claims of widespread voter fraud and lobbying the vice-president, Mike Pence, and Republican members of Congress to try to overturn the count at the 6 January congressional certification. Election officials across the country, along with the courts, had repeatedly dismissed Trump’s claims.

An angry mob of Trump supporters were echoing his false claims as they clashed with Capitol police and broke into the building that day, interrupting the certification of Biden’s victory.

In his request for a meeting with Perry, Thompson wrote: “We would like to meet with you soon to discuss these topics, but we also want to accommodate your schedule.”