Everyone here has seen Facebook rumors portraying refugees as a threat. They’ve encountered racist vitriol on local pages, a jarring contrast with Altena’s public spaces, where people wave warmly to refugee families.
Many here suspected — and prosecutors would later argue, based on data seized from his phone — that Mr. Denkhaus had isolated himself in an online world of fear and anger that helped lead him to violence.
This may be more than speculation. Little Altena exemplifies a phenomenon long suspected by researchers who study Facebook: that the platform makes communities more prone to racial violence. And, now, the town is one of 3,000-plus data points in a landmark study that claims to prove it.
Karsten Müller and Carlo Schwarz, researchers at the University of Warwick, scrutinized every anti-refugee attack in Germany, 3,335 in all, over a two-year span. In each, they analyzed the local community by any variable that seemed relevant. Wealth. Demographics. Support for far-right politics. Newspaper sales. Number of refugees. History of hate crime. Number of protests.
One thing stuck out. Towns where Facebook use was higher than average, like Altena, reliably experienced more attacks on refugees. That held true in virtually any sort of community — big city or small town; affluent or struggling; liberal haven or far-right stronghold — suggesting that the link applies universally.