The arrest of Laurent Nkunda, the Congolese rebel leader and megalomanic butcher of Bukavu, offers a rare chance to end the almost continuous warfare in the heart of Africa. The former army general, who deserted in 2004 to take up arms against the Kinshasa Government on the pretext of defending fellow Tutsis in eastern Congo, was captured inside Rwanda. In a swift and dramatic reversal, his former allies in Kigali, who had backed his marauding to weaken the murderous Hutu militias hiding in the forests, changed sides. Rwandan and Congolese troops acted together to capture him as he crossed into Rwanda. He is likely to be returned to Congo, where he is wanted for alleged war crimes.

General Nkunda is only one of several ambitious warlords who have been terrorising villages in eastern Congo for years. Last year his fighters massacred hundreds of civilians in a series of battles, forcing some 250,000 people to flee in panic as he advanced on the provincial capital of Goma. Motivated as much by the prospect of plunder as by tribal animosities, his troops were contemptuous of the UN force that has failed to halt the bloodshed. But his commanders, angered by his authoritarian style and embezzlement of rebel funds, turned against him.

The brutalities in eastern Congo go back to the 1994 genocide in Rwanda and the failure to capture or disarm the Hutu killers. But warlordism, civil war, the lure of mineral wealth and the ambitions of Congo's neighbours have thwarted all attempts at a settlement, despite the UN's biggest peacekeeping force of 17,000 troops. The new co-operation between Rwanda and Congo may at last give peace a slender chance.