On Sunday, as thousands marched through the streets of Tunis to denounce violent extremism, Tunisian officials announced that security forces had killed the commander of the terrorist group believed to be behind the massacre of more than 20 people at the Bardo Museum earlier this month.

Chief of Tunisian Terror Group Killed

Terrorism experts had been skeptical of early Islamic State claims of responsibility for the attack, which killed several foreign tourists and a police officer. Tunisian Prime Minister Habib Essid alleged Sunday that the attack had been perpetrated by members of the Okba Ibn Nafaa Brigade, a group that has claimed responsibility for numerous deadly attacks in Tunisia since 2012.

As AFP reported, Essid said Tunisian forces managed on Saturday "to kill the most important members of the Okba Ibn Nafaa Brigade including its head Lokmane Abou Sakhr." Sakhr, an Algerian man who was also known as Khaled Chaieb, was reportedly shot at a checkpoint near the border with Algeria, along with eight other alleged members of his group.

Tunisia as Success Story

The Bardo Museum siege prompted worry that the one bright spot of the Arab Spring had regressed into violence. In the wake of the deadly episode, however, the government moved quickly to hold officials accountable, firing a number of police commanders, and efforts to find those linked to the attack quickly found success. And as democracy scholar Larry Diamond wrote in The Atlantic last week, the country's democracy has been resilient. "Alone among the Arab Spring states," he wrote, "it has achieved a remarkable level of political compromise among secular parties and the principal Islamist party, Ennahda."

Several world leaders attended Sunday's rally, during which a tablet commemorating the victims of the shooting was unveiled.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.