EU Warns Teen Online Networks Drive Violent Extremism

Al-Qaeda attacks New York and Washington. The extremists, mostly from Saudi Arabia, entered the United States and trained to become pilots. Wegter's point 25 years on: today's threat to Europe is organized mostly online instead.

In Finland, a 16-year-old boy stabbed three female student colleagues. He allegedly shared a "manifesto" in WhatsApp groups, recorded the attack on Snapchat, and asked on social media for someone to save the video and give it to him after his release. In the manifesto he said he wanted to do something "significant" and "exciting." No political motive was given, according to an EU document on the emerging threat.

In Italy, a 15-year-old boy planned a murder to gain notoriety online, authorities there said. He kept images and videos of assaults, murders, school shootings and child pornography on his smartphone.

In Germany, a 20-year-old man believed to be a leading member of the group 764 faced 123 charges over acts of "an unimaginable level of brutality and inhumanity," including murder, rape and the sexual abuse of children, the EU document said.

Europol logged 45 terrorist attacks across 10 of the EU's 27 countries. None were major mass-casualty incidents and about half were foiled or failed, but six people were killed. A total of 486 people suspected of terror links were arrested in 21 member countries. Jihadist groups, often guided or inspired by networks outside Europe, were behind 24 of the attacks and accounted for more than 70% of the arrests. Around one third of everyone taken into custody was under 18, mostly boys.

Investigators from nine European countries run a disruption campaign against "The COM" and turn up roughly 4,340 linked web addresses.