A person watches a television. His name is Adi, he’s Indonesian, and he works as an optometrist. On the screen are two men who helped to murder his brother Ramli—roughly four decades ago, two years before Adi was even born. The pair are recreating the gruesome act with a playfulness that soon transforms into pride. We watch the footage, then we cut to Adi, and watch him watching it. But his unmoving features—his face remains as stoic as a statue—ensure that we only see our own reactions, projected back to us via his blank slate.

The footage itself was shot by Joshua Oppenheimer, who released The Act of Killing three years ago. It was a compendium of such interviews, allowing the perpetrators of the state-sponsored genocide—many of whom remain wealthy and in high political standing—to self-mythologize themselves on-screen. They were living proof of the cliché about who it is that writes history. The Look of Silence, which stays with Adi and his loved ones, questions more of the killers. But this film pushes them further, and at once becomes a sequel, a companion piece, and a corrective to Act. Oppenheimer studies the faces of the family members as his moving images drudge up a nation’s suppressed history. Parts of Act functioned as garish conceptual art. But Look is portraiture.

The murders being discussed claimed the lives of over one million “communists”—used in Indonesia, as in America, as a euphemism for “people the government dislikes”—and have since been accepted as national lore. Oppenheimer’s close-up shots (which hang on faces long after dialogue ceases, as if waiting for explanations that will never arrive) are divided equally among the classes left behind. The killers are unrepentant, claiming to have acted as a result of either American influence or capitalistic pride. The survivors are accepting of the scenario, citing the afterlife as the only place such heinous actions can be addressed. And the descendents, among them Adi’s children, are taught in school that the acts themselves were but a necessary step on the path to democracy.

In questioning the perpetrators and documenting the culture surrounding the history, Oppenheimer (and his co-director, who—like much of the crew—remains anonymous) finds numerous statements as absurd as that last one. In a line more fit for Dr. Strangelove than a documentary, the son of one killer suggests that “we should all just get along, like the military dictatorship taught us.” But Adi, whose mother considers him a fulfillment of Ramli’s spirit, cannot abide the perpetual distortion of history. In the interviews (conducted while he fits the killers for glasses), he deconstructs false justifications and refutes stock explanations, remaining stone-faced even as threats of further violence emerge—unearthed like the blotted history he’s helping to rewrite.

At first Oppenheimer comments only with his edits. One cut connects the aforementioned schoolteacher’s justification with children playing in a ball pit—two instances of formative socialization. But eventually he enters the drama directly. We continue to cut to Adi watching the footage he had shot previously—as a motif, a reminder, and a response to the perspective of the prior film—and it becomes clear that Oppenheimer is burning bridges he had built for the sake of Adi’s inquisition. More than once, the subjects beg off: “Joshua, stop filming.” But he continues, uncompliant, until the stares become something else: uncomfortable laughter, ignorant concessions to reconciliation, or—most often—silence.

Then, like its director, the footage intrudes upon the interviews. While interviewing the widow and children of one murderer, Oppenheimer and Adi play footage of the late patriarch gleefully reminiscing about his violent, state-approved transgressions. It’s the one thing that cannot be denied: cinema. And once it’s introduced to the interview, the film dissolves into the language of nightmares.

Linearity dissipates as Look cycles through increasingly impressionistic scenes of tranquil home fronts and foreboding landscapes. A mirror to the unexamined evil it surveys, The Look of Silence fractures itself into distressing incoherence.

What can one discern from a photograph of a sociopathic cultural ill? The psychology and politics of denial, for one thing. But Oppenheimer’s treatment of moving images—the way that cinema itself intrudes on the interviews, and onto Adi’s ever-still visage—produces a moral justification for the entire art form. It helps to explain our debilitating reliance on surveillance footage, dash cams, and visual evidence of all kinds. Evil cannot always be comprehended. But it can be filmed, and it can be seen.

THE LOOK OF SILENCE. RATED PG-13. OPENS FRI 7.31. KENDALL SQUARE CINEMA. 355 BINNEY ST., CAMBRIDGE.