Population Zero

"It's sort of a documentary about this one little area in Yellowstone National Park where you can get away with murder," director Adam Levins told me when we first discussed this film back in 2015. This much is true. What follows will dazzle and confound. The brutal, indisputable fact that you can kill somebody on that strip of land and walk away scot free is, if you like, the prestige. The film's genius lies in the decision to reveal it up front.

We begin with Levins' friend and co-director, established documentarian Julian T Pinder, showing us his email. He was contacted anonymously, he says, to draw his attention to the case of a certain Dwayne Nelson who killed three young men in Yellowstone. In was an old case so he didn't see what the fuss was about until he started reading and discovered that Nelson was a free man. Despite the fact that he freely admitted to the killings, nobody had ever managed to bring him to trial. Why not? And could there be something about the case - something so far overlooked - that might yet lead to a resolution?

With a pitch like this, it's difficult to see where a film can go, but layer upon layer of revelations unfold as Pinder and Levins set off to see what they can find out. Along the way, narratives blur and questions arise about just whose story this is. Pinder talks excitedly about how they might solve the case, might prove that Nelson's actions were premeditated and thereby enable a court to take action. Levins tries to hold the line. What kind of film are they making? Meanwhile, there are suspicious phone messages, a package delivered to a motel where they didn't tell anyone they were staying. Pitch black observational humour mingles with spine-chilling moments in the most mundane of locations, and in the vast wilderness of the park itself it feels as if anything could happen.

Levins' photography is beautiful as always, even when he has clearly had very little time to set up. Yellowstone's stunning scenery lends a hand. It's easy to become distracted. Pinder's wide-eyed enthusiasm alternates with moments of sly self-deprecation - and self promotion - especially in relation to his previous film Trouble In The Peace. You will need to pay attention to every little detail to keep up - and yet it's all too easy not to see the wood for the trees. In the end, is it really the truth that matters?

At the heart of this multi-layered and ever-shifting story is a photograph. It's from a 2010 YouTube video, Bear Vs Bison, which, to date, has been viewed almost 2.5 million times. In the photograph, a grizzly bear chases a bison, scorched by forest fire, along a road. Musing on it, Pinder wonders which character he is - the hunter or the hunted. What we don't see - the more terrifying factor - is the fire.