JOHANNESBURG, June 9 -- The buses out of South Africa have started running for the people who came to it for work. Malawi began bringing its citizens home this month, Ghana pulled out hundreds last week, and for at least five Mozambican families there is nothing left to bring home but a body. They were killed, their government has counted, in the kind of violence South Africa keeps promising to stop and keeps not stopping.

The killings came over a single weekend in the coastal town of Mossel Bay, where roughly eight hundred Mozambicans were caught up in the unrest. They are the sharpest edge of a wave of anti-migrant attacks that one report traced through Johannesburg, Pretoria and Durban, driven by vigilante movements, chief among them ...