Kevin Wilson Jr. may still be a student, but his latest film has already picked up two awards and is now shortlisted for Best Live Action Short Film in this year’s Oscars.

My Nephew Emmett tells the true story of Emmett Louis Till, a young African American staying with his uncle, Mose Wright, in Mississippi in 1955. Emmett is accused of whistling at a white woman in a shop and, two nights later, is abducted, tortured and murdered by the woman’s husband and his half-brother.

The film is as simple as it is shocking. Given the brutality and notoriety of the murder, and its subsequent catalytic effect on the Civil Rights Movement in America, Wilson Jr. could have made a 3-hour documentary and still barely scratched the surface. Instead, he creates a snapshot – a microcosmic glance that condenses the entire issue into just 20 minutes of film.

The murder itself is not shown. Nor are we told what happens to Emmett’s killers (nothing, by the way, they were acquitted), nor how the murder would resonate through America. The focus, instead, is on the build-up to the event. We witness the descent of a family from carefree normality to fear and tragedy through a brutal display of racially motivated violence. It encapsulates the precarious existence of African Americans at the time – only a wayward glance or inappropriate whistle away from torture and death.

The film’s tension, though, comes from its perspective. Mose, who is told of Emmett’s actions and fears the repercussions, is placed at the centre of the story. As the rest of the family carries on insouciantly, Mose is consumed by tacit fear for his nephew. The camera trains in on him as he lowers his frail body into the bath, or sits awake at night, wide-eyed, clutching a shotgun. He begs the killers to take his nephew’s place, but he knows his pleas are in vain. By telling the story through the eyes of the calm but world-weary uncle, not the naïve teenager, the film suffuses this shocking story with a disturbing sense of inevitability.

Laura Valladao’s photography is superbly atmospheric, complementing the sombre narrative with dark hues of brown and orange that plunge the sparse Mississippi setting into a perpetual dusk. This technique arguably goes too far in the second half of the film, as the obscurity denies us the details of the characters’ facial expressions. But this is a mere peccadillo that does little to detract from the film’s impact.

My Nephew Emmett’s striking apogee comes in the closing seconds, as the final scene morphs into historical footage of Mose Wright. It is a seamless slip from fiction to reality, serving the viewer the uncomfortable reminder that these events really happened. But, true to the film’s parsimonious style, we are given just 10 seconds of this footage before it fades into the credits. The magic of Wilson Jr.’s film, it seems, lies as much in what it omits as what it shows.