The killing of 14-year-old Keira G. in her home sparked a flurry of posts by far-right groups and individuals alleging the crime had been committed by a migrant, and accusing the authorities of hiding the culprit's identity.
Berlin police spokesman Winfrid Wenzel called the allegations of a cover-up "absurd," noting that police are forbidden from releasing information if it might endanger an investigation. Even after an arrest, suspects are entitled to privacy protection, especially if they are minors, Wenzel said.
A 15-year-old German suspect in the March 7 slaying was arrested Sunday.
Among the social media users facing scrutiny is Lutz Bachmann, the co-founder of German anti-Muslim group PEGIDA, who posted a picture of an innocent boy with the words "beast from the Caucasus ... Chechen Muslim and ex-refugee."
Bachmann later deleted the post, but could face charges of incitement to hatred, a crime of which he was convicted in 2016.
Allegations against refugees were also circulated by members of Alternative for Germany, a right-wing nationalist party that placed third in last year's election after a campaign that focused strongly on crimes committed by migrants.
While rates of violent crime in Germany have increased since the influx of more than a million refugees began three years ago, experts say migrants are no more likely to commit crimes than their German peers.
Several high-profile cases involving refugees have stoked anti-migrant sentiment, especially on social media, prompting officials to warn of the possibility of vigilante violence.
"What happens on the internet after a murder such as this is truly terrifying," Wenzel told The Associated Press, noting that the spreading of rumors and false information put additional pressure on investigators. "We have never experienced a murder case being politically exploited in such a way."
He said there were "certain parallels" to the so-called Lisa case, involving a 13-year-old girl of Russian origin who allegedly was kidnapped and raped by migrants in Berlin two years ago.
Right-wing groups, Russian state media and the country's foreign minister condemned the alleged attack. German police later concluded the girl had run away and made up the kidnapping story.
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