Doug Mastriano has become one of former President Donald Trump’s most important midterm endorsements as the Republican Party’s nominee for governor of Pennsylvania. If elected, he would serve as an important loyalist in charge of a key swing state ahead of a possible Trump run in 2024.

But Mastriano has some baggage that has already attracted unwanted scrutiny, including from the FBI. On Thursday, CNN reported that Mastriano was interviewed by the FBI over his possible involvement in the Jan. 6, 2021 assault on the Capitol Building by an enraged mob of Trump supporters.

The FBI maintains a strict policy on not confirming or denying the existence of any investigation. However, citing a source familiar with the investigation, the network said the FBI questioned Mastriano last summer after photos emerged of him on the Capitol's grounds on Jan. 6.

Timothy Parlatore, Mastriano’s lawyer, confirmed the interview by two FBI agents to the Associated Press and denied his client knew of any plan to storm the Capitol that day.

“He previously was approached and sat for a voluntary interview with the FBI and told them the truth about everything that happened that day,” Parlatore said. ”The FBI cleared him.”

The riot was widely seen as the violent result of Trump and his allies’ assertions that the 2020 presidential election was stolen from him by now-President Joe Biden. The conspiracy theory has been widely debunked in the courts, by Trump’s own Justice Department and in multiple investigations, including by Republican state legislatures.

Regardless, Trump has stuck to his focus on the 2020 election conspiracy theory and backed Mastriano for governor. Mastriano scored a landslide victory in last month's Republican primary and will face Democrat and state attorney general Josh Shapiro in the general election.

A former Army colonel and a Pennsylvania lawmaker, Mastriano has held to Trump’s version of events. While serving as a state senator, Mastriano helped organize buses to Washington in the run-up to the Stop The Steal rally that culminated in the Capitol Riot.

Mastriano insisted that he and his wife remained in the rally area, but video footage discovered online showed the Mastrianos watching rioters storm past the Capitol Police and the two passing through a police barricade. It was this footage that allegedly brought him to the attention of the FBI as well as the congressional committee investigating the Capitol Riot.

Politico reportedon Thursday that Mastriano furnished materials relevant to their investigation into the riot and Parlatore, his lawyer, confirmed Mastriano would sit for a voluntary interview with the committee.