Reviews in the US of The Act of Killing, while mostly positive, typically lurched from one shocking thing that Congo does or says to another. In one scene, for instance, Congo describes exiting a screening of an Elvis musical, “still in the mood of the film,” dancing across the street to a paramilitary office, and “killing happily.” In a sequence of surreal film-noir scenes that layer fiction upon reality upon fiction, until the viewer is unsure what’s real and what’s theater, Congo and his fellow executioners dress in suits and fedoras and take turns playing victims and killers, choking each other with wire—a method they learned from Hollywood that became their go-to technique. At one point, Congo’s neighbor, who has volunteered to play an execution victim, tells the cast of killers gathered on set that he has a story that might fit with the plot. He explains that his stepfather had been abducted and murdered during the middle of the night, and that as a young child he went out the next day with his grandfather to find the body and bury it at the side of the road. “I promise,” the man says repeatedly during his story, “I’m not criticizing you.”

The killers smile and nod throughout, as if only pretending to listen, and then declare his scene too long and complicated for the story they’re trying to tell. Back to filming now, the killers prepare to choke the man with wire.

An important part of Oppenheimer’s approach was to screen a rush edit for the killers and film their response. One might expect Congo to be concerned about his image when he watches a scene of himself demonstrating how he choked his victims, but his only worry is his wardrobe. “I never would have worn white pants,” he says. “I look like I’m dressed for a picnic.”

As the film progresses, Congo and his friends slip, in Oppenheimer’s words, further “down the rabbit hole of self-invention.” And this reveals the effectiveness of Oppenheimer’s theatrical method as an investigative technique. Watching the re-enactments leads the characters to suggest new and more elaborate re-enactments, the filming of which requires them to dig more deeply into their pasts “both as they remember them, and as they would like to be remembered.” As Oppenheimer notes, “The most powerful insights in The Act of Killing probably come in those places where these two agendas radically diverge.” Not only did the re-enactment process capture confessions of crimes that had never been recorded, but it provides insights into the minds of the perpetrators as they attempt to take moments of unimaginable cruelty and mold them to fit their understanding of themselves and their society.

The film is not solely interested in the past, though, nor does it limit itself to the minds of its subjects. In an ever-widening attempt to explain themselves, the killers take Oppenheimer to see some of the most powerful figures in Indonesian society. And these men, rather than attempt to be more subtle or media savvy than the executioners who worked at their behest, amplify the performance of impunity.

We meet a newspaper publisher who was secretary general of the anti-communist forces that participated in the massacre in North Sumatra, and who actually used his newspaper’s building as a base for the killings. He takes Oppenheimer’s cameraman on a tour of his office to see the photos of him with prominent Indonesian politicians. He then confesses casually to using his newspaper as a mouthpiece for anti-leftist propaganda—“My job was to make the public hate them,” he says—and to ordering torture and execution. Near the end of the interview, Oppenheimer presses him on a detail of how the executions were carried out. “Why would I do such grunt work?” he responds. “One wink from me and they’re dead.”

In another scene, we visit a gathering of Pancasila Youth, a paramilitary group that grew out of the massacre and remains active in Indonesia. It claims 3 million members and runs a nationwide network of gambling, racketeering, and extortion operations with tacit approval from the Indonesian government—or at least the approval seems tacit, until Oppenheimer films a government official donning the organization’s orange-an-black fatigues and courting members with a rousing speech that includes lines such as, “We need gangsters to get things done,” and, “Beating people up is sometimes needed.”

Michael Meyer is a CJR staff writer. Follow him on Twitter at @mcm_nm.