GOMA, Democratic Republic of Congo — The lights are out in most of Goma. There is little water. The prison is an empty, garbage-strewn wasteland with its rusty front gate swinging wide open and a three-foot hole punched through the back wall, letting loose 1,200 killers, rapists, rogue soldiers and other criminals.

Now, rebel fighters are going house to house arresting people, many of whom have not been seen again by their families.

“You say the littlest thing and they disappear you,” said an unemployed man named Luke.

In the past week, the rebels have been unstoppable, steamrolling through one town after another, seizing this provincial capital, and eviscerating a dysfunctional Congolese Army whose drunken soldiers stumble around with rocket-propelled grenades and whose chief of staff was suspended for selling crates of ammunition to elephant poachers.

Riots are exploding across the country — in Bukavu, Butembo, Bunia, Kisangani and Kinshasa, the capital, a thousand miles away. Mobs are pouring into streets, burning down government buildings and demanding the ouster of Congo’s weak and widely despised president, Joseph Kabila.