He returned to the country the following winter to stand trial and ultimately was exonerated. Prosecution appeals were finally exhausted last June, a year after the arrest.
Philadelphia was picked for the "Palaces" premiere largely because fans here were among the first outside Lamb of God's home base of Richmond, Va., to embrace the band when it first broke out around 2000.
Lamb of God has called Philly its second home, and its 2005 DVD, "Killadelphia," featured live performances from the Troc.
The fan base
"As the Palaces Burn," which runs 90 minutes (and is unrelated to the band's album of the same name), falls smoothly into three acts: The first shows Lamb of God rehearsing and touring and includes segments with fans from around the world; the second details Blythe's arrest and the band's response; and the final act focuses on Blythe and the trial.
As first pitched to Argott by band manager Larry Mazer, of Voorhees, N.J., the documentary was supposed to explore what Lamb of God's music means to some of its ardent fans. The crew filmed fans' stories in Colombia, Venezuela, Mexico, India and Israel, as well in the United States.
"The film, in its origin and its concept, was basically an attempt to turn the camera away from us and showcase the fans and kind of what it is like to be in this genre as a fan of the music," guitarist Willie Adler said in a telephone interview last week.
Filming was nearly finished when Argott - also known for "Art of the Steal," his documentary about the Barnes Foundation's move to the Parkway, and "Rock School," about the Paul Green School of Rock Music - was faced with an entirely different story in the wake of the arrest.
"It would have been foolish and near impossible to ignore this event and say, 'Oh, we're making a film about their fans,' " Argott, whose 9.14 Pictures coproduced the film, said in a recent phone interview. "When this happened, the filmmaker in me was, 'Wow, this is an incredible opportunity to be on the inside of the story as it is unfolding.' And now you have a built-in outcome . . . something that gives closure."
Argott said that he had spent enough time with the band members by the time of Blythe's arrest to know that he had to ask about continuing to make the film.
"It took a little bit of time to even get to that place to even have the conversation," he said. "Once they realized that this was going to be a pretty significant event, they all came on board and decided to keep the cameras rolling."
Mazer said that he was blindsided by the arrest, which made few headlines in the mainstream U.S. press. Lamb of God was scheduled to play large festivals in Germany and Finland, and had decided to return to the Czech Republic during some down time, because of their success there in 2010.
"Supposedly, when we did the date in 2010, the show was fine, the show ended, everybody went home . . . it was just another show," Mazer said.
Unknown to the band at the time, Daniel Nosek, 19, had died within days of attending the 2010 show. Prosecutors alleged that he suffered fatal head injuries after diving onto the stage and being pushed off by Blythe.
When he got the call about Blythe's arrest, Mazer said, he got in touch with the Czech promoter, who recalled talking with officials about Nosek's death two months after that earlier show, but no one had been in touch about it since.
The band was hit hard financially for eight months, with its future in limbo and Blythe's legal costs soaring. Besides selling "Free Randy Blythe" memorabilia, the band auctioned other memorabilia and equipment.
"We knew that we had to support our brother and do it by any means possible," Adler said. "We believed in Randy. We knew he was innocent. We knew there was no malevolence. There was no action on Randy's part to cause this."
Once the trial began, Argott had to overcome some legal hurdles to keep filming. Originally, he was told that he could film only opening statements and the verdict, but eventually the judge allowed filming in the courtroom.
Although the outcome is known, the moment in the film when the verdict is read - in Czech - is powerful. Blythe was unsure of his fate until his translator told him. The film shows him turning to give a thumbs-up to Argott and Mazer in the courtroom.
"The core audience that has been following the story is gonna know the outcome, but it's how you tell that story and how you engage people in that moment," Argott said. "You can Google and see that Randy was exonerated, but to see what happened when he got exonerated, that's the moment. That's what it's all about."
Metal's softer side
Besides the compelling story, Argott is pleased that "As the Palaces Burn" shows the band members' reflective side.
"They're all very smart guys," Argott said. "There's a comment that I laugh at a lot of times - 'I'm really surprised that they are articulate.' . . . I don't know what that is that people automatically make that assumption that if you play heavy-metal music, then you're somehow not smart. That is an attitude that prevails a lot of times and it is not correct.
"These guys are really smart. And Randy is a very, very thoughtful, gentle guy. They all are, and I think it comes across in the film."
Like Argott, Adler hopes the film offers a more accurate, if unexpected, portrayal of heavy metal.
"I would love for especially just moviegoers, not even fans of metal, to come away with a deeper appreciation for this scene," Adler said.
That said, the impact of Nosek's death has not diminished for band members.
"It's still rather difficult, because it's something that we all deal with on a daily basis," Adler said. "Knowing that this happened at one of our shows, and trying to make all of our future endeavors and future shows as safe as possible for everybody involved. It's still kind of surreal that this has all happened . . . It's still taking time."
"As the Palaces Burn," 9 p.m. Sunday (doors open at 8), Trocadero Theatre, 1003 Arch St. All ages; general admission tickets, $15. Prerecorded video Q&A session with band members and "That Metal Show" host Eddie Trunk follows screening. 215-922-6888, thetroc.com.