Early on in their investigation into the bomb attack on the Borussia Dortmund football team, German police said they were working on the assumption they were dealing with terrorism.

“On the basis of the modalities of the crime, we assume there was a terrorist background to the attack,” Frauke Köhler, spokeswoman for Germany’s federal prosecutor’s office told a press conference on 12 April, the day after the atrocity.

While a precise motive, she said, remained unclear, “two suspects from the Islamist spectrum” were being observed by investigators. One, allegedly an Isis member who had led one of the group’s death squads, had been detained. He was later arrested. It was repeatedly said there was no evidence to link him to the attack.

But based on three claims of responsibility discovered near the scene of the crime, Köhler said: “an Islamic background to the attack seems possible”.

Yet she made it clear investigators had considerable doubts, not least because there was a great deal of discrepancy between the letters and other Isis claims of responsibility. Language experts quickly drawn into the investigation said they were of the view the unusual wording suggested the letters could have been a deliberate ploy to steer investigators in the wrong direction and to quickly blame radical Islamists for the attack.

An acknowledgement of responsibility had also been claimed by a leftwing, anti-fascist group criticising Borussia Dortmund for failing to do enough to tackle rightwing extremism among its fan base, but there were also serious doubts as to its authenticity.

Further confusion was caused by the apparent emergence at the weekend of a statement emailed to a Berlin newspaper by rightwing extremists who cited Adolf Hitler and highlighted the failures of multiculturalism, which made headlines around the world.

A Sunday Times story headlined: “Dortmund attackers wanted to incite backlash against Muslims,” further muddied the waters, by citing a police source as apparently telling the paper the attack probably had a far-right background. Its reporting was widely repeated.

German news outlets, by contrast, were by and large straightforward in their reporting. The July shooting in Munich last year, in which a German-Iranian teenager gunned down nine people at a shopping mall, was a lesson to police and media about the dangers of jumping to conclusions. Initial reports that radical Islamists were responsible for the shooting, and that several gunmen were likely at large, led to a huge degree of panic and rumour and possibly a delay in the 19-year old’s capture.

Despite some international media’s attempts to claim an Islamist motive, publicly the German police never veered from saying that they remained open-minded and were “looking in every direction”.

By the time they issued another statement to German news agency DPA on Monday saying “the pendulum swings neither in the direction of rightwing extremism or Islamism”, they already had their sights not on an Islamist or a neo-Nazi, but on a stockmarket speculator and electrical engineer. A tip-off had initially put them on his trail just a day after the attack.

It cannot be excluded that Sergej W. was driven by a political motive. But following the arrest of the 28-year-old German-Russian in Tübingen, police said they suspect his motivation was first and foremost a money-making one. He took a gamble that shares in Borussia Dortmund would slump if the team was annihilated or injured by the bombs he allegedly planted.

But long before Sergej W.’s arrest, plenty of others had quickly drawn their own conclusions, firmly pinning the crime variously on Islamists and Muslim refugees, despite the lack of evidence.

Nigel Farage tweeted on April 13: ‘I am sorry to say we will see this again in Europe”.

I am sorry to say we will see this again in Europe. https://t.co/XDsw8eOq4C — Nigel Farage (@Nigel_Farage) April 13, 2017

Tommy Robinson, former leader of the English Defence League, wrote: “Borussia Dortmund bus attack suspect ‘was Islamic State fighter’.”

Borussia Dortmund bus attack suspect 'was Islamic State fighter' https://t.co/dbx7DAcBbh — Tommy Robinson (@TRobinsonNewEra) April 13, 2017

Paul Joseph Watson, the editor-at-large of the alt-right website Infowars, insinuated the attack was carried out by a Muslim immigrant and was therefore a slap in the face for Dortmund players and fans who had given a welcome to refugees.

Dortmund's players and fans welcomed Muslim "refugees" and they still got attacked. pic.twitter.com/Imr28XfKO0 — Paul Joseph Watson (@PrisonPlanet) April 12, 2017

In Germany, the attack was widely exploited by prominent members of the populist extremist Alternative für Deutschland (AfD) to pin blame for the attack on the chancellor, Angela Merkel, and even top footballers for standing up against racism.

Petr Bystron, the party’s leader in Bavaria, used a Facebook video post to vent his anger that the attack was a result of the decision by Merkel’s government to welcome refugees. “It is just terrible where this miserable ‘do-goodery’ has already brought us. We finally need responsible and expedient deeds and no more of the lip service of these complete ‘wannabee liberals’,” he said.



He attacked players such as Philipp Lahm from FC Bayern for speaking out against rightwing propaganda and attacking the AfD, adding that he hoped that, as with all the other members of the elite, “a light will now go on”.

Reimond Hoffmann, the deputy leader of the AfD’s youth wing, Die Junge Alternative, said the attack was a slap in the face for everyone who had helped refugees, but implied Borussia Dortmund only had itself to blame because it had sent out a Ramadan greeting to Muslims around the world.

Despite no connection ever having been made between refugees and the attack, the AfD continued to spread the message that the bombing, like the Berlin Christmas market attack in which 12 were killed, was a direct result of Germany’s refugee policy which had made Germany less secure. It posted the message: “Thankyou Merkel! Attack on BVB: Islamists responsible! From football to Christmas markets: No area of our lives is safe anymore.”

There was, however, no response on Friday evening from any of them to the news of Sergej W.’s arrest.

Writing in Die Zeit, Yassim Musharbash said: “AfD politicians and other organised or freelance Islamophobes for ever and a day use anything that in any way looks like a possible Islamist attack to make their political hay, often before it’s clear what the real background of a crime is. With the wisdom of hindsight they are then proud if they’ve guessed correctly. Or quiet if they’ve been wrong.”