“So tired of the same old crud / Sweet baby, I need fresh blood,” go the lyrics to the theme tune of “The Jinx,” Andrew Jarecki’s six-part documentary about Robert Durst, which came to a conclusion on HBO last night. The song, by the rock band the Eels, at first seemed hardly a subtle choice for a series that began by chronicling the investigation of the killing and dismemberment, fifteen years ago, of Morris Black, Durst’s onetime neighbor in Galveston, Texas, and went on to explore Durst’s possible culpability in the disappearance of his first wife, Kathie Durst, in 1982, and the execution of his onetime best friend, Susan Berman, in 2000. Durst, the misanthropic, self-regarding, tic-ridden son of a real-estate tycoon, had sought out Jarecki and offered himself as an interview subject after seeing “All Good Things,” the filmmaker’s fictionalized account of the Dursts’ marriage. He was, the framing of the show suggested, a cold, vampiric psychopath who had yet to be held responsible for his murderous appetites.

By the end of the sixth episode, however, it had become unsettlingly unclear exactly whose taste for blood was being chronicled in “The Jinx,” and whose appetite was being satisfied. The finale was structured around the preparation for a follow-up interview, in which Jarecki was to confront Durst with new evidence that pointed to his guilt in the murder of Susan Berman. The episode had the pace and tone of reality television. There was the breathless use of a “confession cam,” into which Jarecki spoke about his fears for his own safety in light of his growing convictions about Durst’s past. There was also obfuscation of the time line for dramatic effect. In one instance, Chip Lewis, Durst’s lawyer, was seen reacting to a new piece of evidence—an envelope inscribed by Durst that strongly resembles an envelope in which an anonymous note was sent to the L.A. Police Department, alerting them to Susan Berman’s death—before Durst is seen being confronted with it. This seems an unlikely sequence of events, unless Lewis is as bad at being a lawyer as Durst is at being a husband, friend, and neighbor.

The episode, like the rest of the series, was riveting television in the way that footage of a tsunami is riveting: horrific, inexorable, and barely watchable. Seeing Robert Durst willingly acknowledge the first letter, which had been belatedly found in Susan Berman’s effects, and then watching him as Jarecki produced the letter sent to the Los Angeles police was to witness a process of inward disorientation in real time, and to participate in it, too. We are accustomed to watching actors convey the experience of a horribly dawning realization—it’s easy to imagine Ian McKellen playing the role of Durst. But it was quite another thing to find oneself having been induced—willingly, avidly—into witnessing Durst’s appalling recalibration.

Even more shocking was the scene that followed: Durst, still wearing a live mic while going to the bathroom, was overheard talking to himself while urinating: “Killed them all, of course.” The show presented this as Durst’s confession, though the possibility remains that it might have been Durst’s ventriloquism of what he imagined Jarecki’s thought process to be. (It would not be the first time Durst had spoken to Jarecki as if he were a skeptical outside observer of his own defense.) Thus ended the episode, and the show.

When first confronted with the twin letters, Durst belched as if he was about to vomit, and he was surely not the only one made bilious by the scene as it unfolded. (Sickening in a more straightforward manner was the show’s lurid reenactment of Susan Berman’s murder—an actress falling to the ground in sensuous slow motion—which was shown repeatedly, an operatic aestheticization of her death.) Watching “The Jinx” brought to mind the brilliant first episode of the British drama series “Black Mirror”: a Swiftian satire in which the public watches the Prime Minster sexually humiliate himself on television. In a pub, a mob of viewers is moved from titillated vengefulness to pity and then to self-recrimination, appalled by the experience of witnessing what they’d longed to see.

At the same time, the airing of Durst’s sensational bathroom soliloquy raised questions that the show itself declined to answer—the explanations evidently withheld for dramatic, rather than journalistic, reasons. With such a recording in hand, what was Jarecki’s calculus in balancing his self-proclaimed desire to see justice done with his wish, after ten years of research and labor, to make a groundbreaking television show? The claim, in the Times, that Jarecki and his team overlooked the existence of the bathroom recording for two years, seems worthy of a six-part investigation of its own. (The filmmakers, having been quizzed on the time line of events as represented, have cancelled forthcoming interviews.)

Before the finale aired, the news broke that Durst had been arrested in New Orleans and charged with Susan Berman’s murder. It will be up to the lawyers to determine what, if any, of Durst’s actions or statements as recorded by Jarecki will be admissible as evidence. If Durst is finally convicted—if it is determined that a guilty man was entrapped in “The Jinx”—Jarecki will no doubt be congratulated for bringing Durst to justice. Indeed, he already has been: Jeanine Pirro, the Westchester district attorney who investigated the death of Kathie Durst, told the Times that Jarecki and his producer, Marc Smerling, “did what law enforcement in three states could not do in thirty years.”

Meanwhile, those of us who formed the audience for the show are left to contend with our participation in an extralegal spectacle that, against all odds, transformed the unsympathetic Durst into a pitiable quarry. Whatever Durst’s culpability, “The Jinx” became, by the miniseries’ end, a grotesque concatenation in which vigilante investigation was queasily merged with commercial sensationalism. A quarter century ago, Janet Malcolm, in her now classic essay “The Journalist and the Murderer,” characterized the betrayals that were, she argued, inherent in the relationship between a reporter and his or her subject. What our changed times call for is an examination of the complicity that transpires between the producers and the consumers of quasi-journalistic entertainments like “The Jinx.” Because every viewer who is not too stupid or too full of himself to know what was going on knows that what we did was morally indefensible.