However, when it comes to documentary films, this notion of trustworthiness takes on a deeper meaning. What is willing suspension of disbelief for fictional films is replaced with the assumption that what you are watching is a representation of honest-to-goodness fact. Veracity becomes important, but documentaries still have stories to tell, and many are, in the telling, subject to the same narrative and cinematic strategies as fiction. Unlike in fictional film, where it seems that unreliable narrators and ‘based on true events’ plots lost their impact long ago, the illusion of fact is still a battlefield in documentary. The simple request that you, as a viewer, trust the filmmakers as they spin you a tale, gives documentaries great potential to mess with your expectations, to lure you into a false line of thought, and to con you. The Imposter, out this week, is the story of one incredibly audacious con. In the mid-1990s, a kid called Nicholas Barclay went missing from his Texan home. Just under three years later, after his family had given up the search, they heard that he had been found in Spain. He had reportedly been kidnapped, tortured and raped by some shady Europeans, but was ready to return home. There’s an explanation for this, of course. The boy wasn’t Nicholas Barclay at all, he was a con-man, but that didn’t seem to bother the family, who took him in regardless. Remarkably, this is not a spoiler. One of The Imposter’s great strengths is that it is as much the story of Frederic Bourdin, the career con-man, as it is about Nicholas’ family. The film is told in a style very reminiscent of director Errol Morris (The Thin Blue Line, Tabloid), where engrossing interview footage, archive material and re-enactments are cut together, culminating in a documentary that plays out like a thriller. It’s this absurdity that grows throughout the film, helped along by a quirky bunch of characters who could have danced off the pages of a Coen Brothers script. There’s the somewhat odd family, a suspicious federal bureaucrat, and an old private eye called Charlie Parker, whose Falstaffian bulk, slicked back hair and delicious over-pronunciation (‘Ah-doh-bee Pho-do-sharp’) make him a prime role for John Goodman in the fictional remake. But, joking aside, there’s a greater mystery at play here. It springs from the central question: why is the family so easily conned? Is it just simple grief, or is it something more sinister? Once the film starts to turn its attentions towards the family, and Bourdin himself begins to paint a rather frightening picture of domestic life, all previous certainties about the film become complicated. After all, who do we trust? The victimised family? The baffled authorities? Or the con-man himself? In a stroke of genius, this real-life mystery keeps you guessing until the end, and leaves you uncertain which lie you want to believe. It’s a real water-cooler ending. Sure, there’s the resolution of the case itself, which saw Bourdin charged for wrongful appropriation of an American passport and sentenced to six years imprisonment, but there’s a sneaking suspicion that there’s something we’re missing. A vital detail that, if we dig deep enough, might help to explain everything. But is that just another fiction? Is our love of storytelling getting the better of us? Have we been conned by first-time director Bart Layton? If you’re one of the unfortunate souls who frequently forgo the documentary portion of your film diet, then you should chow down on The Imposter. It has characters, themes and a story that rival any fiction film – and it goes to prove that factual, legal accuracy does not always tell the entire truth. We’re only just over the hump of 2012, but The Imposter is one of the best films of the year. Trust me. Follow our Twitter feed for faster news and bad jokes right here. And be our Facebook chum here