In a 1986 letter to Gerry Gable, the late thriller writer and crime journalist Stieg Larsson called the assassination of the Swedish Prime Minister Olof Palme as "one of the most unbelievable and amazing homicide cases I've ever had the unpleasant job of covering". Gable was the editor-in-chief at Searchlight, a radical magazine in the UK and Larsson, 32, was working as an illustrator at the Swedish news agency, Tidningarnas Telegrambyra (TT), harbouring hopes of becoming a crime journalist.

For the next 18 years or so, Larsson would feverishly obsess and research about the unsolved assassination of Palme, who was shot dead a few minutes past 11 pm on February 28, 1986 after he had walked out of Stockholm's Grand Cinema with his wife. Simultaneously, Larsson also penned the bestselling Millennium trilogy of crime novels, which earned him fame, though posthumously. In 2004, Larsson died of a heart attack aged 50. Following his death, all of Larsson's extensive research on Palme's assassination, which included letters, interviews, newspaper cuttings among others, were reduced to cold files.