True crime is as popular as ever.  Mainstream interest in podcasts like Serial and long-form docs such as Making a Murderer is clear evidence of the public appetite for tales of murder, mayhem, and perhaps even justice. Véréna Paravel and Lucien Castaing-Taylor’s Caniba—the subject of which is notorious Japanese killer Isseu Sagawa—is a film that is more disturbing and powerful than most anything else in the current true crime zeitgeist.

Paravel and Castaing-Taylor are part of Harvard’s Sensory Ethnography Lab, which describes itself as “an experimental laboratory that promotes innovative combinations of aesthetics and ethnography.” The lab uses “analog and digital media, installation, and performance, to explore the aesthetics and ontology of the natural and unnatural world.” The duo’s prior collaboration, Leviathan (2011), is an experimental documentary about, of all things, fishing. Multiple cameras were handed off to a crew during a long expedition on a trawler. Leviathan transforms the seemingly mundane activities of a fishing crew into a surreal journey into an alien world filled with creaky machines and teeming with strange life forms.

Just as Leviathan turned the nature documentary upside down, Caniba subverts the conventions of true crime . Isseu Sagawa brutally murdered and cannibalized Dutch college student Renée Hartevelt in 1981. Upon his release, he became a minor celebrity in Japan and leveraged his deeds into books—he made an autobiographical manga about his crimes—and other jobs, including a role in a pink movie. Sagawa is still alive, but he is mentally ill, physically incapacitated, and unable to do much of anything without assistance.

Caniba’s subject matter is disturbing enough but what makes this documentary so powerful are the aesthetic choices made by the directors. The filmmakers focus their gaze on Isseu Sagawa himself. Lingering close-ups of the killer’s stricken face and crippled body dominate the film. He stutters, drools and struggles his way through the interviews. This unflattering presentation reveals the killer as frail and weak. The overall effect of this approach creates contradictory emotions. Sagawa’s infirmity may invoke sympathetic reactions but this sympathy is offset by his deeds and his blatant exploitation of his infamy.

What’s more, Jun Sagawa—the killer’s brother and caretaker—participates in Caniba as a facilitator. Jun is initially presented as a moral contrast to his brother,  but he eventually pushes an already discomfiting situation into wholly unexpected territory. Caniba immerses the viewer in the private world of the Sagawa brothers, and in the process, reveals some horrible realities that most of us would rather ignore.