And yet the draconian measures implemented by the Karimov regime have not solved the problem of Islamist extremism in Uzbekistan. They have only pushed problem underground and, ultimately, abroad. Saipov isn’t the first native Uzbek to have been implicated in a terrorist attack. Last summer’s airport bombing in Istanbul was carried out by an Uzbek man, along with co-conspirators from other Central Asian countries. An Uzbek drove a truck into a crowd in Stockholm in April. Last week, an Uzbek was sentenced to 15 years in prison by a New York court for providing material support to ISIS. Uzbekistan has provided some 1,500 soldiers to ISIS in Iraq and Syria, according to the Soufan Group. ISIS has claimed that Uzbeks were responsible for some of its most high-profile suicide bombings in Iraq. In November 2014, the largest Uzbek faction fighting in Syria pledged its allegiance to the Taliban.

In 2014, seemingly acknowledging that government restrictions on the practice of Islam weren’t working, Karimov asked Russia’s Vladimir Putin for help in dealing with his extremist problem. Putin shared Karimov’s concerns, but he was in the process of exporting his own Islamist threat to Syria, turning a blind eye to thousands of Russian citizens going to join the fighting as long as they stayed out of the way during the 2014 Sochi Olympics. This year, Russia has overtaken Saudi Arabia and Tunisia to become the largest supplier of foreign fighters to ISIS. Men from Russia’s Muslim republic of Dagestan told me in April that when they ventured into ISIS-controlled territory in Syria, they found a Russian-language subculture on the streets of cities like Tabqa, where fighters and families from all over Central Asia were united by that region’s Soviet lingua franca. On the Syrian border with Turkey, they encountered busloads of Central Asian women—mothers going to wrest their children from the clutches of the Islamic State.

Now, as ISIS continues to lose territory, those Russian-speaking fighters from Uzbekistan and other post-Soviet countries are scattering. And though there’s so far no evidence that Saipov ever traveled to Syria to train, he didn’t have to. There is plenty of extremist material online, and vehicular attacks like the one in New York—and in Stockholm, Berlin, and Nice—require no particular expertise with weapons, which explains both why they are so hard to prevent and why ISIS actively encourages them. It also suggests that the Islamic State may come to rely on such attacks more as their territory shrinks, and with it, their capacity to coordinate more sophisticated attacks.

Consider this: The bomber who detonated himself in the St. Petersburg metro in April, killing over a dozen people, was an ethnic Uzbek from Kyrgyzstan. He had never trained in Syria or Iraq, but he had been in touch with his countrymen who had been.