RELATIVES of Stieg Larsson, the bestselling Swedish novelist whose posthumous international appeal has made him the toast of the publishing industry, are locked in a bitter dispute over an inheritance worth millions and a laptop computer.

The legal battle between Larsson’s girlfriend and his father and brother could have been plucked from the pages of his three crime novels and is stirring just as much passion in Sweden, where at least one in three people has read them.

For months the nation’s attention has been focused on the plight of Eva Gabrielsson, a 54-year-old architectural historian. She lived with Larsson for 30 years until his death in 2004 but has inherited none of the estimated £10m he has earned since because they were not married.

“I think it’s a great injustice,” Gabrielsson said last week. “It would have been beyond Stieg’s worst nightmares to know that someone other than me was handling the rights to his books and to know that the money we planned to invest is gone.”

Larsson, a crusading journalist whose books have sold more than 12m copies around the world since his death, had for long been estranged from Erland Larsson, his father, and Joakim Larsson, his brother, according to Gabrielsson.

“Stieg distanced himself from them, like he did with others who were different from him,” she said. Yet because the writer died intestate they inherited everything.

“My lawyer has been trying to get an agreement with them that would give me the literary rights, but they have never been in favour of that,” said Gabrielsson.

She is campaigning for a change in the law so that common law spouses can inherit even when there is no will.

Erland and Joakim also inherited half of her Stockholm flat. In 2005 they offered it to her in exchange for Larsson’s laptop computer, which contains a 200-page manuscript, an unfinished sequel to the so-called Millennium trilogy.

“My legal adviser called it extortion,” she said. “I refused to hand over the computer.”

Speculation abounds that Larsson sketched out plots for another six stories on the laptop. Someone - perhaps even Gabrielsson, who helped to research the original books - might end up finishing them.

“It would be as difficult as trying to finish a painting by Picasso,” she said, adding that the only book she was writing concerned events since the death of Larsson, who collapsed from a heart attack after walking up seven flights of stairs to his office on a day when the lift was out of order.

Conspiracy theorists said he might have been murdered, as he had made numerous enemies with his exposés of racist groups and the Swedish far right and had apparently lived for years under death threats. However, friends blamed his 60-a-day smoking habit and punishing workload.

He met Gabrielsson at a rally against the Vietnam war in 1972. They moved in together two years later. For many years Gabrielsson supported Larsson, who earned little as a journalist. She said last week that Larsson’s legacy was being treated as though it were “a plot of farmland or a herd of sheep”.

Instead, the rights to his books were, she said, intellectual property that should not be “left to people who never took part in their development”.

A statement from the Larssons claimed that Gabrielsson was “blocked in her anger” and accused her of ignoring invitations to take part in important decisions concerning the Larsson oeuvre.

“We are inundated with requests for permission to make plays and cartoon strips out of Millennium,” they said. “Quentin Tarantino and Brad Pitt would like to buy the rights for a remake of the film. We want her opinion.”

A Swedish Millennium film opened last week in France, where Larsson inspires such fascination that books about him have been written with titles such as The Mystery of the Fourth Manuscript.

The Larsson craze has spread and the first book, in which Mikael Blomkvist, a journalist, teams up with Lisbeth Salander, a computer hacker, to investigate the disappearance of the niece of an ailing tycoon, appeared in Britain last year as The Girl With the Dragon Tattoo. The second volume, The Girl who Played With Fire, came out in January.

The fact that Gabrielsson will get none of the royalties has caused outrage among fans.

“I think it’s incredibly nasty what money does to people, especially in inheritance disputes,” said Noomi Rapace, the Danish actress who plays Salander in the Millennium film.

Norwegian fans have launched a “support Eva” campaign on the internet to help her to pay legal bills and to offer her “moral royalties”. They recommend donating £3 “if you’re annoyed”, £7 “if you’re upset” and £15 “if you’re really furious at the way Eva Gabrielsson has been treated”.

The Girl who Kicked the Hornet’s Nest, the third book of the trilogy, will appear in Britain later this year while in Sweden, at least, they are waiting with baited breath for the Gabrielsson memoir. It was referred to, jokingly, by one commentator last week as The Widow who Dreamed of Taking Revenge.

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