You can read it here.
The body of the letter:
Pursuant to the authorities set forth in House Resolution 503 and the rules of the House of Representatives, the Select Committee to Investigate the January 6th Attack on the United States Capitol (“Select Committee”) hereby transmits a subpoena that compels you to produce the documents set forth in the accompanying schedule by March 1, 2022, and to appear for a deposition on March 10, 2022.That last footnote is real important. It leads here.
The Select Committee is investigating the facts, circumstances, and causes of the January 6th attack and issues relating to the peaceful transfer of power, in order to identify and evaluate lessons learned and to recommend to the House and its relevant committees corrective laws, policies, procedures, rules, or regulations. The inquiry includes examination of how various individuals and entities coordinated their activities leading up to the events of January 6, 2021.
The Select Committee has tremendous respect for the roles and responsibilities of federal, state, and local elected officials and we do not seek information from you that is related to official actions that you took as an elected lawmaker. At the same time, we have a solemn responsibility to investigate fully the facts and circumstances of these events.
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. For example, we understand that you have knowledge of and participated in a plan to arrange for an alternate slate of electors to be presented to the President of the Senate on January 6, 2021,1 and we understand that you spoke with former President Trump about your post-election activities.2 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 elegates to the Electoral College.” 3 We have an interest in understanding these activities and the theories that motivated them.
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.”4
We would like to better understand these statements and expenditures, events that you witnessed or in which you participated, and communications we believe you may have had with national, state, and local officials about the outcome of the November 2020 election.
Accordingly, the Select Committee seeks documents and a deposition regarding these and other matters that are within the scope of the Select Committee’s inquiry. A copy of the rules governing Select Committee depositions, and document production definitions and instructions are attached. Please contact staff for the Select Committee at 202-225-7800 to arrange for the production of documents.
That's the reporting in PA Spotlight quoting Mastriano saying he'd seen both breaches of The Capitol - evidence of his lying to the public when he said that he and his wife left the area at the first sign of trouble.
PA State Senator Doug Mastriano has been subpoenaed by the January 6 Committee!
