STOCKHOLM—A World Cup soccer game should be a welcome relief from a country’s bitter and polarized general elections.

But Germany’s winning goal during overtime in the June 23 game against Sweden unleashed a social media firestorm, the aftermath of which is still dominating headlines.

The Swedish election is shaping up to be a referendum on immigration policy, and the nationalist-conservative Sweden Democrats look like they may become the biggest party in parliament, despite a decadelong effort by establishment media and all other parties to stop their growth.

There is a fierce ongoing debate about what constitutes “Swedishness,” touching on issues of racism, immigration, segregation, and crime, while Sweden’s current Social Democrat/Green government has made feminism and identity politics cornerstones of its political rhetoric.

These issues have now exploded into the realm of World Cup soccer. Even before Sweden’s first game, played against South Korea, Left Party parliamentarian Daniel Riazat commented on Twitter that the starting team was the “whitest ever,” implying that coach Janne Andersson was racially biased in selecting players.

And then, when midfielder Jimmy Durmaz—born in Sweden to Assyrian-Syrian parents—caused the foul that gave Germany their winning goal on a free kick, his social media accounts were flooded with abuse, some of it clearly racist in nature.

While the overwhelming response has been condemnation of the racist attacks and support for Durmaz, the incident quickly became politicized. Viktor Sodermark of the ultra-nationalist party Alternative for Sweden tweeted that the Swedish team “chose to put diversity in the field and was punished, as usual,” implying that coach Andersson’s choice to put Durmaz in the game was somehow motivated by political correctness.

But as the abuse against Durmaz became international news, questions arose about its origins.

First, a fake FIFA Twitter account was found to have been instrumental in spreading the news of the attack on Durmaz. Second, screen dumps of some strange-looking hate comments against Durmaz began circulating, along with evidence that these accounts had been created only recently, and in some cases terminated right after the comments were made.

Many of these comments featured the hashtag #sd2018, a reference to the Sweden Democrats and the 2018 election. Sweden Democrat leader Jimmie Akesson was quick to express support for Durmaz, but his political opponents were equally quick to accuse his party of fostering an atmosphere of racial hatred.

While media was flooded with op-eds decrying the supposed rampant racism in Sweden, a narrative about there being a concerted troll effort began circulating on social media. Some concluded that it was orchestrated by nationalists to stir up hate, while others suspected leftists or the Social Democrats of trying to discredit the Sweden Democrats.

Others again spoke of possible “psy-ops,” with concern about foreign powers, mainly Russia, meddling in the Swedish election.

“It’s insane to declare war and fight to reclaim something that’s not been taken from us in the first place,” she wrote.

“I believe my findings refute that,” he said. “These are completely ordinary youngsters commenting.”