Acclaimed new film The Mastermind, starring Josh O'Connor, tells the story of an art robbery gone wrong. It's inspired by a wave of similar thefts during a decade known for upheaval.

In May 1972, two men walked into the Worcester Art Museum in Massachusetts and hurried out carrying four paintings by Paul Gauguin, Pablo Picasso and a supposed Rembrandt (now believed to be the work of one of his students), holding a group of visiting high school students at gunpoint and shooting a security guard in the process. With the stolen artworks' worth tallying up to $2m (£1.5m), the New York Times ranked it among "the largest art robberies in modern times". Some say it even inspired a far more famous crime nearby: the 1990 heist at Boston's Isabella Stewart Gardner Museum, in which $500m (£370m) of art was looted, making it the costliest theft in US history full stop, with the crime remaining unsolved.

The Worcester heist was orchestrated by career criminal Florian "Al" Monday, but the game was up after the two thieves he hired for the raid boasted about their exploits in their local bar. Within a month, the paintings were safely retrieved from a pig farm in Rhode Island and returned to the gallery. "Ironically, Monday – before he was an art thief – had a band, and I have the 45 of his record," writer-director Kelly Reichardt tells the BBC. Her new film The Mastermind, which is released in the US this weekend, is loosely inspired by the chain of events that followed the Worcester robbery, as well as the wave of art heists that followed over the course of that decade.

Praised by The Guardian's film critic Peter Bradshaw for locating "the unglamour in the heist", Reichardt's thoughtful art crime caper dismantles the usual rules of the glitzy, sensationalised heist movie. Blockbusters have long popularised the idea that there is something classy about this category of crime, particularly when it involves art: think, for example, of the 1999 version of The Thomas Crown Affair, in which Pierce Brosnan plays a very suave billionaire orchestrating a raid on New York's Metropolitan Museum of Art.

Reichardt's take on the genre adopts a slower pace and more exacting eye for the way in which its art robbery cataclysmically unfolds. Josh O'Connor takes the title role as the brains behind the operation: JB Mooney, a middle-class, well-educated art school drop-out now ailing as an underemployed carpenter in Massachusetts. Under pressure from his well-to-do parents – a retired judge (Bill Camp) and a socialite (Hope Davis) – to repay their loans to him, he cases the fictional Framingham Art Museum for a heist. But from the moment that one of his henchmen asks how he plans to sell on the stolen paintings – which would be difficult due to their recognisability – the scheme begins to go awry.

Reichardt came across an article about the 50-year anniversary of the Worcester Art Museum robbery while working on her previous film, Showing Up (2002), a comedy drama about two rival sculptors, and decided to use the story as the foundation of her next feature. All that was left to do was to create the character of JB. "The political ideas, the genre ideas – these are things you think about and study, but then you have to let go of all that and concentrate on the details of the film you're making with what your character situation is like," says Reichardt. "If you start to get down into the minutiae of those things and don't concentrate on the bigger strokes, then by nature........

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