Bulgarian officials said on Saturday that they had arrested and charged a 16-year-old student who had been radicalized by the Islamic State with planning a terrorist attack.

The Islamic State had recruited the teenager, who is from Plovdiv, in a process that started over social media, Deputy Prosecutor General Ivan Geshev said Saturday at a news conference in Sofia, Bulgaria’s capital.

“This is a classic example of recruitment and radicalization of an individual, in this case an underage person,” he told reporters, describing the case as a “personal tragedy.”

Read more: New York Times