If the events recounted in “Tread” had not occurred in real life, you might mistake any synopsis of its storyline for a treatment written by some grindhouse-cinema aficionado as a tribute to ‘70s rural-revenge thrillers. Indeed, Paul Solet’s remarkably absorbing and suspenseful documentary often plays like the dark flip side of that audience-stoking subgenre — think Jonathan Kaplan’s “White Line Fever” or Jonathan Demme’s “Fighting Mad” — in which working-class protagonists transform tools of their trade into blunt-instrument weapons while battling corrupt oppressors.

For roughly the first third of the movie’s running time, Marvin Heemeyer, a fiftysomething welder and muffler-shop owner in the small Colorado mountain town of Granby, certainly seems to fit the genre stereotype of a hard-working, straight-shooting guy who doesn’t become violent until he’s pushed too far. To be sure, that initial impression is sustained largely by Heemeyer himself, who’s heard on recordings he made before his date with destiny, and a group of interviewees that includes his former girlfriend. And even during the early going, it’s a tad troublesome to perceive the resolute fervor in his taped supplication: “God bless me in advance for the task which I am about to undertake.”

For a considerable stretch, however, Solet craftily structures “Tread” in such a way that it’s easy to accept Heemeyer as an avenging angel.

After moving to Granby in the early ‘90s, we’re told, Heemeyer purchased at public auction a two-acre site where he established the muffler shop. As the business prospered, he developed friendships with a few locals — including fellow snowmobile enthusiasts, who marveled at his ability to manufacture custom bumpers for their vehicles, and the aforementioned girlfriend, Trisha Macdonald, who says that, at least during their early days as a couple, she “always felt safe” with him.

But the good times didn’t last. Heemeyer recalls that, as early as his 1992 land purchase, he got crosswise with a businessman who had also bid on the property — and who had strong ties with the powerful family that controlled most of Granby and the town’s government officials. Over the years, Heemeyer lost a series of legal battles against the city council, which he claimed singled him out for harassment by strictly enforcing laws pertaining to water and sewage access. By the time his adversaries won their own battle for zonal approval to build a potentially polluting cement plant directly across the street from his shop, Heemeyer was ready to take drastic action.

Really, really drastic action.

This is the point where, in conventional rural-revenge melodramas, you’re inspired to start cheering for our hero, and admiring his ingenuity, as he hashes out an audacious plan for settling scores. Long before this point in “Tread,” however, nagging doubts about a possibly unreliable narrator give way to full-blown certitude that, instead of being a plucky underdog, Heemeyer was a delusional sociopath who truly believed God was on his side.

Solet manages his movie’s wrenching reversal of course by adding new witnesses to his lineup of interviewees — including, naturally, many of the people accused of treachery by Heemeyer — and utilizing many slicky produced scenes of “historical reenactment” to enhance a riveting narrative that inexorably devolves into a worst-case scenario.

Over a period of approximately a year and a half, Heemeyer methodically transformed a Komatsu D55A bulldozer into a steel-and-concrete-armored tank outfitted with automatic weaponry. He took it as a sign of God’s will that he was able to fit the dozer inside his muffler shop in the first place. And when his work-in-process wasn’t detected by an insurance inspector, Heemeyer concluded in his taped final testament: “I wasn’t supposed to get caught.”

On June 4, 2004, Heemeyer revved up his armored vehicle and set about demolishing private and public buildings throughout Granby while police repeatedly proved unable to stop the weapon of selective destruction. “Tread” grippingly depicts the rampage with a potent mix of news footage, reenactments and testaments from witnesses who by and large sound like they still can’t quite believe, much less explain, what they witnessed. Asked to account for Heemeyer’s actions, one Granby citizen theorizes: “He just spent too much time alone.” Another one adds: “You never know what gets into people.”

“Tread” abounds in memorable images and interviews that range from darkly comical to deeply disquieting. (Before he enters his mean machine, the reenactor who represents Heemeyer shaves his head — just like Travis Bickle in “Taxi Driver.”) But one sequence manages to be both amusing and unsettling all at once, through dint of its sheer simplicity. Solet focuses tightly on two pre-digital devices in the same frame: A cassette recorder, which plays one of Heemeyer’s self-justifying rants; and a microcassette recorder, which plays the rebuttal of a Granby resident who maintains that, no, that’s not what happened. Not at all.

By the way: If any of this sounds familiar, that’s quite possibly because Heemeyer’s assault on Granby partly inspired Andrey Zvyagintsev’s Oscar-nominated 2014 film “Leviathan.” But if you are among the many who do not recall reading or hearing anything about this amazing event at the time it happened in 2004 — credit Solet for saving the most gobsmacking of his stranger-than-fiction twists for last.

Film Review: ‘Tread’

Reviewed online, Houston, March 7, 2019. (At SXSW Film Festival: Documentary Competition.) Running time: 89 MIN.

  • Production: (Documentary) A Great Point Media presentation of a Zipper Bros. Films and Sutter Road Picture Co. production in association with Roebourne Media, Hypnotic. Producers: Sean Stuart, Glen Zipper, Doug Liman, David Bartis, Gene Klein, Robert Halmi, Jim Reeve. Executive producers: Victor Shapiro, Raphael Swann.
  • Crew: Director, writer: Paul Solet. Camera (color): Zoran Popovic. Editor: Darrin Roberts. Music: Austin Wintory.
  • With: Patrick Brower, Glenn Trainor, Casey Farrell, Trisha Macdonald, Stuart Spencer, Larry Thompson, Gary Thompson.