“Such is the irresistible nature of truth,” wrote Thomas Paine in the “Rights of Man,” “that all it asks, all it wants, is the liberty of appearing.”

When Robert Durst, the creepy yet hypnotic subject of HBO’s documentary “The Jinx,” appeared to confess to the deadly crimes of which he had long been suspected, the 71-year-old New York real estate scion did not simply offer great TV.

He reminded us why crime dramas remain the most popular narrative in virtually any genre: They reassure us that no matter how complicated the crime, how clever or powerful the criminal, the truth will eventually make itself known.

It is this belief, in the supremacy and almost supernatural power of truth, that fuels the various forces of civilization. Politics, religion, philosophy, psychology all depend on the existence of, and search for, some essential nature of things. In art, illumination comes in many guises: the soaring strings, the poetic monologue, the soul bared suddenly in a glance.

Or as happened during the final moments of the six-part series by Andrew Jarecki, the off-camera mutterings of an old man using the bathroom.

Durst was charged with murder March 16 for the death of his longtime friend Susan Berman, who was found shot execution-style in her home on Christmas Eve 2000. He still must have his day in court, however, and he was previously acquitted of murder in connection with the death of a neighbor he admitted dismembering.

In the HBO series, Durst is seen talking to himself in what seems to be two separate personas. He creates a deeply disturbing prose poem to the human drama, culminating in what sounds eerily like the call and response of good and evil: “What the hell did I do? (moaning sound). Killed them all, of course.”

Whether by editing or actuality there the monologue ends, its final words possibly providing, at long last, the grail of all detective drama — the confession.

In early episodes “The Jinx” explored how the influence of a New York dynasty helped Durst escape culpability in three separate cases — the disappearance of his wife, Kathie, in New York, the killing of his friend Susan Berman in Los Angeles, and the dismemberment of Morris Black in Galveston, Texas. Durst has not been charged in connection with his wife’s 1982 disappearance.

Throughout the series, Durst was mesmerizing in his composure, occasional dry wit and careful, clearly rehearsed language. “I am complicit in Kathie not being here,” he said early on in reference to his wife, who remains missing, presumed dead.

But the series, which seemed content to remain a provocative, sometimes coy, character portrait, took an enormous turn in the penultimate episode when a hand-addressed letter from Durst to Berman surfaced. The envelope’s block lettering appeared to perfectly match the writing used in a note to the Beverly Hills police that could only have been written by Berman’s killer. In both instances, Beverly was misspelled “Beverley.”

The sixth and final episode concluded with Jarecki presenting Durst with the two samples. As he had throughout the series, Durst maintained a preternatural sense of calm, even as he acknowledged the similarity.

At one point, as Jarecki pressed him, Durst gagged and covered his face with his hands, but otherwise, he remained calm and steadfastly denied writing what was referred to as “the cadaver note.” On his denials, the interview ended.

An overhead camera continued to roll, capturing Durst, Jarecki and the crew as they left the room. Still miked, Durst went to the bathroom, and off screen launched what would become the film’s final moments and perhaps the strangest and most effective monologue in recent cinematic history.

In the bathroom, Durst began talking to himself. Those of us prone to self-criticism both silent and audible could certainly relate to the remonstrative tone, which makes the nature of the words, and their shifting emotion, even more chilling.

“There it is, you’re caught … You’re right of course, but you can’t imagine … Arrest him … I don’t know what’s in the house …. Oh, I want this …. What a disaster … He was right, I was wrong …. And the burping. (choking sound) … I’m having difficulty with the question … What the hell did I do (moaning sound)…. Killed them all, of course.”

It’s an extraordinary moment in television, proof not that truth is stranger than fiction, but that fiction is often a reliable guide to truth.

As fans of crime fiction know, most detectives rely on two things: the vanity of the killer and the inevitable emergence of the truth. As everyone from Miss Marple to Harry Bosch says at one point, keep people talking long enough and they will tell you what you need to know.

Or as Shakespeare put it first and best: “Murder can not be hid long … at length the truth will out.”