The fascination with murderers in popular culture has been present in cinema from its very early days and continues to this day. Be it in the form of the latest Netflix true-crime documentary or a killer-focused drama – with recent examples covering everyone from Charles Manson, to ted Bundy and Jeffrey Dhamer. The unspeakable acts of violence of these individuals is a well many viewers keep coming back to.

It is a perverse fascination, wanting to get into the minds of people who commit such acts, but one many of us can't help but be enthralled by. It is not rocket science to see why we're drawn to such stories. It comes – one hopes – from a place of trying to understand what would drive another person to take a life, and for the filmmakers, it is a chance to help make sense of chaos.

In the case of Nitram, Justin Kurzel's portrait of Martin Burnell, the shooter behind Australia's bloodiest mass shooting in Port Arthur in 1996, it is a film and filmmaker trying to get to the heart of the human being behind the event that forced the country to radically change its gun laws. It has already caused upset among those closest to the events, with many questioning why such a topic or individual needs to be explored. The film itself is undeniably impressive, and in Kurzel's hands becomes a tense and volatile experience that uses the expectation of violence as a tool to challenge our assumptions of the ‘serial killer' drama.

Caleb Landry Jones stars as Martin – or Nitram to his town – an individual who has grown up as the focus of ridicule from his peers. Suffering from a learning disability and depression, which has put a strain on his relationship with his equally emotionally fraught parents (played by Judy Davis and Anthony La Paglia). When he strikes up a relationship with an ageing heiress (Essie Davis), Martin moves out of his home and is given a sense of freedom he has never experienced before. But when a series of tragedies strike, Martin is pushed deeper into his depression and begins to plan something unspeakable.

Many critics of Nitram have discussed its attempts to humanise a man behind a bloody event in Australia's history. While one may wonder what much of the point is humanising such a figure to understand what led to him committing such a violent act, to deny he was ever human is a dangerous act in and of itself. Nitram is keen to not justify his actions but explore the limits of empathy its audience may be capable of, fleshing out the details that eventually lead to Port Arthur.

It rarely steps into stereotypical ‘madman' tropes in its depiction of Martin, mainly due to how committed Jones' performance is and how volatile he makes his personality. That is not to say the film never deals with a certain degree of exploitation. It often portrays moments where Martin's behaviour is very unpredictable and drags out certain moments of tension as your mind is left wondering what it is he is about to do and how violent the outcome may be. These moments are deeply uncomfortable, and can leave a sour taste in the mouth as you question the integrity of mounting such moments of tension, which only occasionally boil over into something violent or destructive.

The film is much more nuanced when it approaches the Port Arthur massacre itself, wisely choosing not to dramatise those events, leaving it to the audience's own recollections of the events or the recounting of the aftermath to fill in the gaps. The film also slightly shifts its focus in the final third towards the gun laws in Australia at the time, and the text at the end would seem to suggest that it is intended to be a warning about both the gun laws in Australia and across the world. But it weirdly feels like an afterthought when it comes around, with the film clearly much keener on being a character study for the most part, particularly when diving into the relationship between Martin and Helen.

Jones and Davis both portray the fractured minds of their characters with a sensitivity that proves hard to look away from, and while the film ultimately leaves you with a lingering sense of dread and despair, there are glimmers of hope and love throughout that make you wonder ‘what if.' Likewise, Judy Davis and Anthony La Paglia put in two very effective performances as Martin's parents, clearly, two people who have been driven to their last nerve raising Martin – there's not a lot of tenderness between them, particularly between mother and son which builds into the inevitable dread of events.

Nitram is a difficult film to sit with after a time, and even more difficult to write about. It is undeniably well made, expertly performed and does for the most part manage to avoid a sense of sensationalism that other films of its kind often trade in. It lingers with you and leaves you in an unshakeable funk, the sense that you've gotten too close to something you shouldn't have. That makes it hard to recommend, but it is for the most part a sensitively handled account of the man behind something unforgivable.

NITRAM releases digitally, on DVD and Blu Ray on Tuesday 20th September.