Kurt Kuenne’s documentary Dear Zachary: A Letter To a Son About His Father is many things – a tribute to a murdered friend, a historical record for the deceased’s child, a portrait of near-unfathomable love and devotion, and an evisceration of a country’s judicial and child protective services systems. It’s also a manipulative, tearjerking thriller that, functioning as a sustained, anguished primal scream, is as emotionally devastating as any film, fiction or non-, released this year. After the unexpected 2001 murder of his childhood best friend, 28-year-old doctor and gregarious Jack Black-lookalike Andrew Bagby, director Kuenne set out to interview Bagby’s friends, family and colleagues (of which there were many), as well as cull mountains of archival footage, with the aim of crafting a loving eulogy. Events, however, soon transformed the nature of his film – far from simply a heartfelt biography that captured the nuanced humanity of his subject, Kuenne found himself immersed in something of a horror story when it became clear that the woman Bagby had been unhappily dating while attending med school in St. John, Newfoundland, 40-year-old mother of three Dr. Shirley Turner, was a psychotic most likely responsible for the crime. Without revealing more, the ensuing saga, which would come to involve a stunning bombshell and an even more dreadful second tragedy, soon turns unbearably harrowing and upsetting. Breathlessly barreling forward, spastically jumping about between the past and present, and poignantly overlapping (and evocatively repeating) sound and image – such as via juxtapositions that reveal the natural and nurtured bonds shared by parents and children – the director’s hectic editorial structure results in a warp-speed, mixed-media, past-present collage that both reflects the complex breadth of Bagby’s life and expresses the overwhelming anxiety and grief of its creator. Kuenne’s concealment of his story’s later-act incidents is unquestionably an attempt to generate dramatic suspense from unspeakable tragedy. Yet his structure also, fundamentally, honors his traumatic in-the-moment experience making the film, as well as honestly seeks to provoke requisite outrage, sorrow and hope over a story at once gut-wrenchingly disturbing and – in the figures of Bagby’s tireless, courageous, selfless parents – astoundingly inspiring.