Nearly a year after an angry mob swept through the U.S. Capitol, ProPublica, Berkeley Journalism’s Investigative Reporting Program and FRONTLINE will air an updated edition of the documentary “American Insurrection” on Tuesday.

The feature-length film, which follows right-wing extremists in the days leading up to the Jan. 6 assault, originally aired in the spring of 2021.

Now, with investigations into the attack still ongoing, the updated documentary draws on fresh interviews with law enforcement sources, congressional leaders and extremism experts to reassess the day’s events and to look to the future.

The new reporting tracks the migration of fringe beliefs into the mainstream and the enduring power of conspiracy theories about the 2020 election. At rallies around the country, correspondent A.C. Thompson found a growing movement intent on overturning the 2020 vote and altering the course of future elections.

Watch the Updated “American Insurrection”

The updated film showcases recently released footage of FBI agents interviewing Daniel Rodriguez, a California man accused of shocking a police officer with a stun gun during the battle for the Capitol, among other charges. “We felt that they stole the election,” Rodriguez said under questioning. “We felt that they stole this country — it’s gone. It’s wiped out. America’s over. It’s destroyed now.”

Rodriguez has pleaded not guilty.

In a new interview, Capitol Police Officer Harry Dunn said the men and women who stormed the building believed they were acting on the orders of then-President Donald Trump — and told police as much while the melee was unfolding. “They were there because Donald Trump sent them — according to them,” he said.

“My No. 1 thought was just to survive,” Dunn recalled. “We were fighting for our lives, fighting for democracy.”

In another new scene, Thompson asks Mary McCord for a status update on the militant groups implicated in the attack on the Capitol — the Proud Boys and militia organizations like the Three Percenters and Oath Keepers. “Within days, literally days, they started finger-pointing. Some dissolved. Some reconstituted themselves,” said McCord, who serves as legal counsel to the congressional committee investigating Jan. 6 and previously held a top counterterrorism role at the Department of Justice.

However, noted McCord, who also leads a legal clinic at Georgetown University’s law school, the movement that sought to reverse the 2020 vote is by no means dead. She pointed to recent polling indicating that tens of millions of Americans continue to believe that the 2020 election was plagued by widespread fraud as well as the vast amount of disinformation already circulating online about the next round of elections, in 2022.

The updated “American Insurrection” premieres Tuesday at 10 p.m. EST, 9 p.m. CST, on PBS stations (check your local listings) and will be available to stream on FRONTLINE’s website, YouTube and the PBS Video App.