The 18-year-old pop singer who headlined Stockholm's We Are Sthlm festival last summer turned to her blog to address media reports of a string of sex attacks at the music event.
Swedish police are accused of having withheld information about the alleged assaults – the majority of which were committed by teenagers of non-Swedish background, according to the Dagens Nyheter (DN) newspaper – out of fear of stirring anti-immigration tensions.
"I think it is completely irrelevant. Assault is assault. Rape is rape. A swine is a swine, no matter their background," Larsson wrote in a blog post which went viral on Tuesday.
The free We are Sthlm festival is put on every year for 12 to 17-year-olds and is held in various locations in the city centre, including Kungsträdgården, a large park in central Stockholm.
Last summer, police said that there had been "relatively few crimes and people taken into custody considering the number of participants" in the festival, however documents sent by police to DN and the AFP news agency showed allegations of dozens of assaults – including two instances of rape – at the festival in 2014 and 2015.
The head of the national police said on Monday that a full investigation would be launched into why the incidents were kept under the wraps at the time, as he and his colleagues, as well as mainstream Swedish media, defended themselves against accusations that a cover-up had taken place.
Larsson joined commentators criticizing the police's handling of the situation in her blog post.
"Trying to hide something like this only ends up being worse. I would also argue that it's a shame that the police feel obligated to do this, that ethnicity suddenly becomes completely crucial when it's somebody who isn't blond and called Erik," she wrote.
The story has sparked debate both in Sweden and abroad with some advocating that Swedish police and media alike should be less restrictive about reporting suspects' backgrounds.
But others, including Larsson, argue that the debate about ethnicity in the wake of attacks in Cologne and Stockholm risks overshadowing the overarching issue of violence against women.
"Men rape. Swedish men rape. Non-European men rape. The whole thing feels very undemocratic and gloomy. In short, the bottom line is: the police did the wrong thing. The focus should obviously be on men's behaviour towards women in general," wrote Larsson.
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Sweden currently has the highest rape rate in Europe. However this is partly because the country records allegations in a different way to most other countries, tracking each case of sexual violence separately.
So for example if someone says they were raped by a partner every day for a fortnight, officers will record 14 potential crimes. Elsewhere, many countries would log the claim as a single incident.
Larsson however ended the note with a message encouraging women to stand up for themselves.
"Hope all girls out there are doing well. Take care of yourselves! And if you seen anyone being molested, punch him on his dick," she wrote.