Edvard Munch's masterpiece The Scream can be seen as a depiction of many things: mankind's impotence before nature and history, a self-destructive rage at our own insignificance, or plain, old-fashioned existential angst. It doubtless tells us something about the human condition that Munch's lurid portrait of a hairless goblin freaking out on a mountain road overlooking the Oslofj ord is, if one measures art by price, one of the half-dozen most valuable paintings of all time - in May 2012, one of the four versions of The Scream Munch created between 1893 and 1910 sold at Sotheby's in New York for just short of US$120 million (NOK690m), a world record for an art auction.
The Scream can also be imagined to be a reasonable depiction of the expression on the face of an art-gallery director who has just noticed a space on the wall where the first-ever version of The Scream had been hanging. At around 11.20am on 22 August 2004, a pair of masked bandits - at least one of them armed with a .357 Magnum pistol - walked into Oslo's Munch Museum and, to the surprise of several dozen museum visitors, yanked the painting from its hook and bolted, pausing en route to also help themselves to Munch's rather gentler Madonna. A bystander on the street outside photographed the robbery in progress, the waiting getaway driver popping the black Audi's hatch to receive one of Norway's most prized cultural treasures. It was the last time The Scream would be seen in public for over two years.
"It was a Sunday," recalls Petra Pettersen, who for 16 years has been the curator of paintings at the Munch Museum, "so I was at home. I heard about it on the radio. I was shocked, of course, though I knew the security at the museum was really not so good. But then nobody expected something like this in Norway."
They should have. Roughly 10 years earlier, a version of The Scream belonging to the National Gallery in Oslo had been stolen. It was recovered a few months later in a sting operation involving Norwegian and British police. (In a touching demonstration of Scandinavian fair play, the thieves were later released, after appealing their sentences on the grounds that the British detectives had entered Norway using false identities.)
But installing high-tech security systems for high-profile artworks is expensive and often arguably redundant. The best protection a painting as well known as The Scream has - at least in theory - may be its own fame. Though it is worth a fortune, there's little point in stealing what can't be sold - and few billionaires are willing to risk imprisonment to purchase a painting they can't tell anyone they own.
So what's the point of stealing it? Julian Radcliffe has had more reason than most to consider the motivations of art thieves. Since 1991, Radcliffe has run the Art Loss Register (ALR), a London-based database of missing and stolen art. The ALR has assisted in the recovery of hundreds of paintings and other artefacts - including, most recently, a Matisse taken from Stockholm's Museum of Modern Art in 1987. Radcliffe admits that paintings are superficially attractive targets: "Nowhere else do you find millions of dollars just hanging on a wall, so the actual theft is a very low-risk enterprise - especially during opening hours when, if the thieves are armed, the priority is to get them out of the building as fast as possible, to protect the gallery's other visitors."
It's profiting from the crime afterwards that is tricky. "I've had lots of contact with people who've stolen art or financed the stealing of art," says Radcliffe. "They haven't usually thought through what they're going to do with it."
In 2006, six men went on trial charged with the theft of The Scream, though at that point it was still missing. Three were acquitted, among them well-known drag racer Thomas Nataas, who persuaded the court he'd hidden the paintings in his Batmobile-themed tour bus because his life had been threatened. Three were convicted. Petter Rosenvinge got four years for knowingly selling the getaway car to the thieves. Petter Tharaldsen, who drove the car, was sentenced to eight years. Bjorn Hoen, the alleged ringleader, received seven years. In a bid to prompt them to part with information about the whereabouts of their loot, Tharaldsen and Hoen were also told that, pending the recovery of the paintings, they would have to pay a fine of NOK750m to the city.
The pair was spared this daunting expense in August 2006, when Oslo police received a tip-off. They'd worked hard for this lead, running the biggest surveillance operation in Norwegian history, tapping more than 70,000 phone calls. Norwegian newspapers at the time reported that the source was a lawyer acting for David Toska, the leader of a violent raid on the NOKAS cash depot in Stavanger in April 2004 - the biggest heist to ever take place in Norway and a crime that had resulted in the death of a police officer. Police had long thought there might be a link between the crimes, speculating that lifting the famous paintings was intended to divert attention and resources from the investigation into the cash heist.
This theory was reinforced by the sorry state The Scream was in when it was returned to the Munch Museum - its captors certainly hadn't treated the painting as if they valued it. "There were several damages," says the Munch Museum's Biljana Topalova-Casadiego, who oversaw the painstaking restoration process. "The most obvious was damage by liquid in the lower left-hand corner, but the paint surface was cut in several areas where the protective glass in the frame had been broken - the thieves had tried to get rid of the frame, I think because they were worried it had a tracking device. And then it was stored for two years in conditions quite demanding for such a fragile piece. But it could have been worse - we'd heard so many rumours about it being burned or destroyed."
The Scream was briefly put on show shortly after its recovery, before undergoing nearly two years of patient repairs. It was a delicate process, complicated by the fact that Munch had painted The Scream on cardboard.
"We stopped at the level of preservation," says Topalova-Casadiego. "We didn't retouch anything. Cardboard is harder to work with than canvas and the cardboard that Munch painted The Scream on is very thick, so you can't access the painting from the back. So some water damage was irreversible, unfortunately, and is still visible - but we were worried that if we tried to do something about it, there was a danger of making it worse."
It's been back on permanent display in the Munch Museum since 2008, but if any other budding art thieves are tempted, stealing The Scream would be rather more of a challenge today than it was in 2004. By the estimation of Trygve Lauritzen, the Munch Museum's head of security since 2010, NOK40 million has been spent on ensuring that The Scream stays where it is. Visitors are now screened as if they were boarding an aircraft; a sluice-style gate controls the flow of people in and out of the painting's sanctuary; cameras record everything - and, cautions Lauritzen, "there are other measures that we don't talk about."
But while The Scream is now safer than it was, Munch's anguished protagonist will always have some reason to be nervous. "There are some thieves who are drawn to the spectacular," says Julian Radcliffe at the Art Loss Register, "whether that's out of ego, bravado, even a sense of professional pride."
"Criminals do their risk analysis like everyone else," says Munch security chief Lauritzen. "If they think it looks too hard, they'll go somewhere else - and the visual effect of the cameras and X-Ray machines, and metal detectors is very positive in that respect. But you can never be sure about anything in this world. It's not likely and it would be difficult, but you never know."
Want more Munch?
A few highlights of Munch 150, a year of events celebrating the 150th anniversary of Edvard Munch's birth
Stockholm, until 12
May The Thielska Gallery hosts a major exhibition of Munch's work from 1880 to 1910. Paintings include Despair, The Sick Child and a portrait of Friedrich Nietzsche.
Edvard Munch's Mothers
Fredrikstad, 1 June
Documentary premiere about Laura Catherine Munch, Edvard's mother who died of tuberculosis when he was a child, and her sister Karen Bjølstad, who raised the young artist and helped nurture his talent.
Munch | Warhol
New York, until 27 July
The American-Scandinavian Foundation brings together two of the most influential artists of the 20th century. Lithographic works by Munch will be exhibited alongside the Warhol screen prints they inspired.
Book your tickets www.norwegian.com