Doug Mastriano is subpoenaed by the committee investigating the Jan. 6 Capitol attack

The congressional committee investigating the Jan. 6, 2021, attack on the U.S. Capitol has issued a subpoena to Doug Mastriano, the Pennsylvania Republican state senator who is running for governor.

The panel said Tuesday that it sent subpoenas to six people, including Mastriano, demanding information “about efforts to send false slates of electors to Washington and change the outcome of the 2020 election.”

“Based on publicly available information and information produced to the Select Committee, we believe that you have documents and information that are relevant to the Select Committee’s investigation,” Rep. Bennie Thompson (D., Miss.) wrote in a letter to Mastriano that was dated Tuesday.

Citing Mastriano’s public statements and news accounts, Thompson said Mastriano participated in a plan to get the GOP-led state legislature to send a pro-Trump slate of electors to Congress on Jan. 6, spoke with former President Donald Trump in the aftermath of the election, and was present on Capitol grounds the day of the riot.

“We understand you participated in these activities based on assertions of voter fraud and other asserted irregularities and based on a stated belief that under the U.S. Constitution the ‘state legislature has the sole authority to direct the manner of selecting delegates to the Electoral College,’” the letter says. “We have an interest in understanding these activities and the theories that motivated them.”

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It cites a Nov. 28, 2020, tweet by Mastriano that wrongly alleged there was “mounting evidence” Pennsylvania’s election was compromised — in which case, the senator said, the state legislature “has the sole authority to direct the manner of selecting delegates to the Electoral College.”

That statement was consistent with a legal argument developed by Trump allies claiming Vice President Mike Pence could reject pro-Biden slates from key swing states such as Pennsylvania. That idea has been widely discredited by mainstream legal scholars.

The letter also notes that Mastriano appeared outside the Capitol on Jan. 6, when a pro-Trump mob stormed the Capitol and delayed certification of Biden’s victory. Mastriano has said he didn’t enter the building.

“Based on your public statements, we understand that you were present during the attack on the U.S. Capitol on January 6, 2021, and that you witnessed ‘agitators … getting in the face of the police’ and ‘agitators … start pushing the police up the [Capitol] steps,’” the letter says.

The subpoena demands Mastriano share documents by March 1 and appear for a deposition March 10.

“We’re seeking records and testimony from former campaign officials and other individuals in various states who we believe have relevant information about the planning and implementation of those plans,” Thompson said in a statement.

A Mastriano spokesperson didn’t immediately respond to a request for comment.

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The subpoena comes after the Democratic-led U.S. Senate Judiciary Committee issued a report in October saying Mastriano pressured Justice Department officials to investigate bogus claims of widespread fraud in Pennsylvania’s 2020 election.

At the time, Mastriano said the report’s allegations were “part of an ongoing, desperate attempt to distract from what progressive policies are doing to our country.”

Mastriano is seen as a top contender in Pennsylvania’s May 17 Republican gubernatorial primary election. He has consistently won the support of about 20% of GOP voters in opinion polls, sometimes leading the field of more than a dozen candidates.

They’re running to succeed Gov. Tom Wolf, a Democrat whose term ends in January 2023.

The congressional committee also sent a subpoena Tuesday to Mike Roman, a longtime Republican operative from Philadelphia who has played prominent roles behind the scenes in Pennsylvania politics.

The letter to Roman said he was involved in a “coordinated strategy” to urge lawmakers in swing states to send alternate slates of electors. He couldn’t immediately be reached for comment Tuesday.

Roman was Trump’s head of Election Day operations in 2020, after previously working in a mysterious role in the Trump White House. He has a long history of warning about voter fraud and poll monitoring, including disseminating a 2008 video from North Philadelphia showing two New Black Panther Party members outside a polling station, a clip that drew significant interest from conservative media outlets. Roman oversaw Trump’s “election integrity” team in 2016.

The committee has heard testimony from more than 550 witnesses, Thompson said, “and we expect these six individuals to cooperate as well as we work to tell the American people the full story about the violence of January 6th and its causes.”

Staff writer Jonathan Tamari contributed to this article.