Every now and again I’m reminded that feature documentaries not only requires a serious commitment of time and patience on the part of the filmmakers, but also of the dilemma they must face regarding when to quit filming and present their findings. With a scripted drama, you know even before you start shooting (well, most of the time) how the story will play out and conclude. Documentary makers, on the other hand, will often start filming because they find a subject worthy of investigation, and they rarely know how subsequent events will unfold or even whether anything interesting will actually happen. An interesting premise will not necessarily make for an interesting movie. Then there’s the matter of when to put down the camera and move into the editing room. Some stories build to a natural conclusion – a moral or legal battle that must be won or lost, for example – but others could potentially drag on for years and never provide the film with an ending beyond, “and they are still fighting for justice to this day.” However dedicated to their subjects they may be, documentary filmmakers still have to eat and pay the rent, and it must be a tough call to stay with a story for months or even years in the hope of a development that may never come that will neatly wrap up the film.

If it seems from that intro that I’m warning against getting your hopes up for Benjamin Ree’s new documentary feature The Painter and the Thief, and suggesting that it never makes good on its initial promise and doesn’t know how to bring its story to a satisfying conclusion, nothing could be further from the truth. Not only does the film have an intriguing premise, the story it tells has more twists than a good many thrillers and it has an absolute gift of a final turn of events on which to end. It’s also a film that you’re going to get more out of if you go in cold, so rather than throwing out the usual spoiler warnings, I’ll be avoiding getting into specifics of how the story at the film’s centre unfolds.

Karl Bertyl poses for Barbora – image courtesy of NEON

As I suggested above, it has a hell of a hook. After relocating to Norway, Czech painter Barbora Kysilkova created two large and striking canvases that were on exhibition at the Galleri Nobel in Oslo. One night both were stolen, and while surveillance footage made it easy for the police to identify and arrest the thieves, only career criminal Karl-Bertil Nordland shows up for the trial. Barbora and her partner Øystein are in attendance, and at one point Barbora approaches Karl-Bertil and asks him directly about the paintings, but he claims not to recall what he did with them as that period of his life is now a drug-fuelled blur. Then, in the first of a string of unexpected turns, Borbara asks him if he would be willing to model for her. Surprisingly, Karl-Bertil agrees, and an unlikely if problem-peppered friendship starts to develop between these two seemingly mismatched individuals.

It’s the sort of story that fuels that hoary old claim that truth is somehow stranger than fiction, not because it is – seriously, how could it be? – but because what would likely be dismissed as far-fetched in a drama has to be accepted as genuine in a documentary. Director Lee admits that he came to the story early in the development of Barbora and Karl-Bertill’s friendship and thus had to restage elements and draw on footage shot by a friend of Barbora’s to set up the story (I’m also guessing that Barbora’s audio-only courtroom conversation with Karl-Bertil was recorded surreptitiously by Barbora herself). Yet by blending naturalistically staged elements with fly-on-the-wall coverage, he achieves an unforced level of visual and storytelling continuity from an early stage that doesn't waver during the three years in which events play out. I also have to assume that Lee formed a strong bond of trust with both of his key participants, one that allows him to continue filming when many subjects would either walk away or demand that the filmmaker cut the camera. As a result he captures both Barbora and Karl-Bertil in moments of  considerable emotional vulnerability and delivers an early-film emotional humdinger when a genuinely gobsmacked Karl first lays eyes on Barbora’s first painting of him, staring at it with wide-eyed astonishment and becoming so overwhelmed as he approaches it that he breaks down into a flood of tears.

Ree avoids the sort of visual tics that are often employed to jazz up the pace and look of many modern documentaries and his film is all the better for it, instead taking a more old-school observational approach, into which carefully composed shots and staged material (often just single shots in a longer sequence) are seamlessly integrated. His decision not to tell the story in a completely linear fashion is particularly effective, hitting us suddenly with a dramatic development and then hopping back a few months to explore what led up to it. I also liked the way Barbora and Karl-Bertil provide details of each other’s backstories rather than their own, an approach that reveals as much about themselves and how they perceive each other as it does about their respective past lives.

I was gripped from the opening scene by The Painter and the Thief and my attention didn’t waver for a second throughout. It’s a fascinating and disarmingly moving work peppered with genuine surprises, and one that paints – no pun intended but acknowledged nonetheless – a warm, humane and compassionate picture of two seemingly polar opposites who discover a way to bond and communicate. As a result I ended up rooting for them both and particularly for a friendship that at one crucial point looks in danger of damaging Barbora’s loving relationship with the normally supportive Øystein. And if you’re looking for an element that perfectly illustrates the nature of the connection between Barbora and Karl-Bertil, it’s the paintings themselves. An artist of considerable and obvious talent, Barbora nonetheless finds herself struggling financially at one point because galleries are not comfortable with the content of her almost photorealistic work. Karl, on the other hand, though unable to recall what he did with the paintings he stole, freely confesses to Barbora that his prime reason for taking them was that he was so struck by their beauty.

The Painter and the Thief is screening at the BFI London Film Festival on Thursday 8 October 2020 at 21:00 – 21:30 BST