Pennsylvania's Republican nominee for governor on Thursday sued the congressional committee investigating the Jan. 6, 2021, attack on the U.S. Capitol, contesting its legal ability to force him to answer questions about it.

The lawsuit filed by Doug Mastriano contends that the committee lacks appointees of House Minority Leader Kevin McCarthy, R-Calif., and thus does not comply with House rules for conducting a compelled deposition of witnesses.

A properly appointed ranking minority member is necessary for a witness to have access to protections provided in House rules on deposition authority, the lawsuit says.

Last month, Mastriano cut short a closed-door interview without answering questions from committee members. The committee refused to let Mastriano record the deposition, Mastriano's lawsuit said, and Mastriano has concerns about how the committee might disseminate excerpts to the public from a closed-door deposition with him, the lawsuit said.

A committee spokesperson declined comment on the lawsuit, filed in federal court in Washington.

Still, Mastriano's lawyer, Timothy Parlatore, has said his client is willing to voluntarily testify publicly before the panel and has told the FBI that he didn't know about a planned insurrection or any coordination behind the Jan. 6, 2021, attack on the Capitol.

Mastriano, a state senator and retired U.S. Army colonel who won the GOP nomination for governor in May, was in regular communication with Donald Trump as the then-president sought to stay in power despite his 2020 election loss to Democrat Joe Biden.

Mastriano helped organize efforts in Pennsylvania to submit alternate presidential electors beholden to Trump and was seen outside the Capitol as pro-Trump demonstrators attacked police.