This isn’t a “them” problem. This could happen here, too. When resources are scarce enough, people turn on “outsiders”:

Nearby was evidence of what he had endured. A large rock had been used to gouge his torso. Embers remained from a fire that had been part of some torture. Shards of a burned jacket still clung to the victim’s left forearm.

Then, as people stepped closer, there was the faintest of breath pushing against his chest. “This guy may be alive,” someone surmised. As if to confirm it, the man moved the fingers of his right hand.

The jaded crowd neither rejoiced nor lamented. After all, the horrific attacks against immigrants around Johannesburg had already been going on for a week, and in their eyes the victim was just some Malawian or Zimbabwean, another casualty in the continuing purge.

This nation is undergoing a spasm of xenophobia, with poor South Africans taking out their rage on the poor foreigners living in their midst. At least 22 people had been killed by Monday in the unrelenting mayhem, the police said.

But the death toll only hints at the consequences. Thousands of immigrants have been scattered from their tumbledown homes. They now crowd the police stations and community centers of Johannesburg, some with the few possessions they could carry before mobs ransacked their hovels, most with nothing but the clothes they wore as they escaped.

“They came at night, trying to kill us, with people pointing out, ‘this one is a foreigner and this one is not,’ ” said Charles Mannyike, 28, an immigrant from Mozambique. “It was a very cruel and ugly hatred.”

Xenophobic violence, once an occasional malady around Johannesburg, is now a contagion, skipping from one area to another. The city has no shortage of neighborhoods where the poor cobble together shacks from corrugated metal and wood planks.

Since the end of apartheid, a small percentage of the nation’s black population — the highly skilled and the politically connected — has thrived. But the gap between the rich and poor has widened. The official rate of unemployment is 23 percent. Housing remains a deplorable problem.

“That’s fueling the rage at the bottom,” said Marius Root, a researcher at the South African Institute of Race Relations. “There’s the perception that they’re not enjoying the fruits of the liberation.”