How false claims about a mass stabbing led to a riot in the U.K.

In the aftermath, as they swept the streets of charred rubble and reassembled garden walls brick by brick, the residents of Southport tried to make sense of how their seaside town had become the setting of such unimaginable scenes this week.

First the mass stabbings. Then the riot.

On Monday, a yoga and dance workshop with a Taylor Swift theme, designed to occupy children on the first day of summer break, had ended with children running from the studio streaked with blood.

Police charged a 17-year-old boy with murder and attempted murder, but didn’t explain any motive for the attack, which left three little girls dead and seven people in critical condition.

By Tuesday night, violent protests had erupted in the streets. Rioters chanting “we want our country back” threw anything they could find at police, who had only helmets, batons and plastic shields to protect themselves. The rioters smashed the windows of a mosque and looted a shop. They set fire to trash cans, tires and a police van, which burned for hours, filling the skies with black smoke.

Police blamed far-right extremists, who had been whipped up by false reports that an illegal immigrant had been responsible for the stabbings.

More From The Washington Post (subscription required):