For years, film-maker Ado Hasanović has wanted to ask his father, Bekir, about his harrowing experiences during the Bosnian war but their conversations usually ended with curt, abrupt answers that obscured rather than illuminated the past. Bekir might be uncommunicative, but his collection of self-taped films and diary entries recorded during the height of the conflict tells a different story. Culled from this powerful personal archive, Hasanović’s poignant documentary forges a dialogue not just with history, but also across generations.

In 1993, along with two other friends, Bekir formed a film-making collective called John, Ben & Boys in the small mountain town of Srebrenica. As the war escalated, what began as a playful amateur exercise quickly transformed into intentional documentation, as if Bekir was already aware of the genocidal carnage that would soon come. With his small DV camera, he captured the camaraderie of his Bosniak community as well as the terror they endured as Serbian paramilitary groups neared. In scenes of good-humoured gatherings, captured in grainy, textured images, the terrifying sounds of gunshots and bombs ring in the air.

One of the most staggering sequences deals with the infamous massacres at Srebrenica, where thousands of Bosniak men and boys were murdered. Bekir’s recollections of his escape are laid over archival footage shot by unnamed Serbian soldiers, in which Bosniak civilians were tied up and executed. Bekir’s emotive testimony contrasts startlingly with the soldiers’ callous tone, who speak of the dead as if they were not even human; this searing juxtaposition lends humanity and dignity to the victims. In combining different perspectives – past and present, the violators and the violated – Hasanović’s film examines the psychological and the physical scars left by wartime atrocities. Bekir survived the carnage, yet he cannot break free from the long reach of trauma.

• My Father’s Diaries is on True Story from 15 May.