No One Saw a Thing is the story of a murder perpetrated by an entire town, and the lengths to which it went to protect itself. But more than that, it’s a saga about how violence ravages individuals and communities, not only in the moment but in the years afterwards, its traumatic effects trickling down to infect and destroy the future.

Premiering on Thursday, Aug. 1, on SundanceTV, No One Saw a Thing (executive produced by Jason Blum) is a six-part documentary about the tiny rural enclave of Skidmore, Missouri, home to an incident that became so notorious they even made a TV movie about it (1991’s In Broad Daylight, starring Brian Dennehy, Cloris Leachman, Marcia Gay Harden and Chris Cooper): the July 10, 1981 slaying of Ken Rex McElroy, a “town bully” with 37 felonies to his name, and a hulking mutton-chopped 47-year-old who terrorized locals to no end, including shooting multiple people for no good reason. He was, by all accounts, the sort of monstrous bad guy one might find in an old Western.

As in one of those classic films, frontier justice came for McElroy courtesy of the residents of Skidmore (population 440 at the time of the crime). Shaken by the man’s ability to evade jail even after being convicted of a near-fatal attack on a grocery store owner, 50-60 townsfolk convened a meeting to figure out what to do about their McElroy problem. Immediately afterwards, they went down the street to the nearby bar and surrounded McElroy in his truck, where he sat next to his wife, Trena, whom he’d begun dating when she was just 12, and had wedded (while he was married to his third wife) to avoid a statutory rape charge (he also burned down Trena’s parents’ house for objecting to their union). Multiple shooters opened fire on the truck, killing McElroy, as Trena was escorted to safety. When the sheriff arrived (this after he’d also been at the conspiratorial meeting), no weapons were found, nor any ammo shells.

Moreover, there were no witnesses to identify the culprits. Because everyone in Skidmore said they hadn’t seen who did it.

This was, quite clearly, a lie, and No One Saw a Thing is an eye-opening example of both vigilantism and collective silence. In a region known for cowboys and outlaws, Skidmore’s men and women decided that, if the law wasn’t going to protect them from McElroy, they were going to do it themselves. State and federal investigations followed, but none turned up enough evidence to result in a single indictment. And in interviews featured in the series, many residents prove anything but apologetic or remorseful about the killing. Britt Small, in fact, says that the only mistake made during the entire ordeal was not killing Trena too, and that if he had been tasked with carrying out the assassination, he would have done it in McElroy’s driveway, and then set fire to his house. “I’d have burned everything,” he smiles.

Director Avi Belkin employs dramatic recreations to bolster his investigation of this infamous event, which is discussed at length by a variety of candid old-timers, journalists and historians, both now and in copious archival footage from an early-‘80s 60 Minutes segment by Morley Safer. The hard-to-shake impression imparted by this portrait is that McElroy got what he deserved. Though his murder left his 14 children fatherless (a few appear on-camera to lament the toll it’s taken on their lives), No One Saw a Thing paints McElroy as legitimately evil, and Skidmore’s actions—in the face of a law enforcement and court system that refused to properly restrain him—as a justifiable last-resort means of survival in the face of unstoppable cruelty. Even if one doesn’t condone vigilantism, it’s difficult to see his demise as tragic.

There’s more to Skidmore than just McElroy, however, and it’s there that No One Saw a Thing becomes at once more intriguing and more specious. McElroy’s slaying became national news, and in the wake of that hubbub, Skidmore all but dried up. Many talking heads suggest that this was karmic payback for the town’s homicide, and decision to keep the corrosive secret of who perpetrated it. There’s little doubt that the McElroy affair did have a negative impact on the town and its inhabitants, literally and psychologically. But what’s missing from Belkin’s investigation is an examination of the larger socioeconomic forces at play in the United States over the last four decades that might have contributed to a minuscule Missouri outpost such as this (population under 300 now) falling on hard times. Without that, the notion that Skidmore is the victim of biblical-style ruin for its sins feels overblown.

In its later chapters, Belkin also details Skidmore’s plague of subsequent violence, including the 2000 domestic-abuse death of Wendy Gillenwater at the hands of her husband Greg, who finished her off on their front lawn; the still-unsolved 2001 disappearance of Branson Kayne Perry, who vanished into thin air while putting away jumper cables in his backyard shed; and the unthinkable 2004 murder of Bobbie Joe Stinnett, whose unborn baby was cut from her womb by a fellow dog-breeder from Kansas named Lisa Montgomery. No One Saw a Thing smartly relates the first of those two atrocities to McElroy’s execution, insofar as they too were marked by an air of community silence. Furthermore, the series persuasively contends that these crimes indicate that the McElroy episode taught younger Skidmore generations that doing as they savagely pleased was OK—and that they could get away with it, because their friends and neighbors wouldn’t speak out against them.

No One Saw a Thing thus plays as a treatise on the ugly ramifications of brutality and disengagement. It stumbles a bit, though, in trying to make too strong a connection between McElroy and these ensuing incidents, given that the latter were the byproduct of the meth epidemic sweeping through Missouri (Gillenwater and Perry), and an out-of-state lunatic desperate for her own child (Stinnett). The idea that Skidmore cursed itself by killing McElroy is, one can sense in the faces of many residents, true on some kind of psychological level. But in going further than that, the series succumbs to its more melodramatic impulses, epitomized by the purple-prose comments of true-crime author Diane Fanning.

All of which makes No One Saw a Thing an alternately transfixing and frustrating meditation on the short- and long-term costs of violence on a community’s psyche—as well as a conclusive argument in favor of steering clear of Skidmore.