Muslim community leaders in Sri Lanka reportedly said the mastermind behind the Easter suicide bombings radicalized young men through social-media platforms. According to CBS News, a number of leaders from moderate Muslim groups alerted authorities about Zahran Hashim’s online activity. “We believe Zahran radicalized these people using Facebook,” said R. Abdul Razik, one of the leaders. “Especially in the past year, he has been openly calling for the killing of non-Muslims.” Razik said that he’d even asked authorities to take down Hashim’s page, but officials told him it was better to keep the page up so they could “keep an eye on what he was doing.”

One police investigator told CBS they believe two of the bombers—Ilham Ibrahim and Inshaf Ibrahim—in the series of attacks were indoctrinated through “Facebook and YouTube.” The government also reportedly acknowledged that foreign intelligence warnings about the attack were not passed along to ministers, preventing preemptive action to stop the attacks. CNN reports at least 290 people died when the six suicide bombers targeted a church, hotels, and other locations.