On various digital forums, the suspected 16-year-old has talked and shared films with the 15-year-old who was convicted of stabbing a teacher at a school in Eslöv.

In the interrogation about the knife attack, the 15-year-old describes the now suspected 16-year-old as a moral support and when he is asked what part the 16-year-old had in the Eslöv act, he states: "We are like blood brothers and share everything together."

They got to know each other through online games, then they communicated on Skype, but the contact was cut off by the 16-year-old's mother after she heard them swear and use rude language.

Shortly afterwards, they switched to the Discord and Twitch forums.

Fascination with violence

According to the preliminary investigation report from the act in Eslöv, the two young people had discussed school shootings, which weapons were used and different motives.

They shared videos as they synced with music.

Films where people committed mass murder - real films, not documentaries, the 16-year-old states in the interrogation.

They also used to joke about Nazism and racism, the 16-year-old says.

Lisa Kaati, a researcher at the Swedish Defense Research Agency, has studied violent extremism on the internet.

She says that the forums that have emerged have a minimal moderation.

- Many of these forums are characterized by a very widespread culture where there is a fascination with acts of violence, where people share films about previous acts of violence and encourage each other to commit acts of violence, but they also pay tribute to former perpetrators, says Lisa Kaati.

Police methods may need to be adapted

In order to detect potential perpetrators, crime prevention work must also be changed.

The police and the security police's methods need to be adapted to the digital world, says Lisa Kaati.

- We need to look at the same risk factors that you look at in the physical world, for example that you have a fascination with mass murderers or perpetrators of violence, that you pose with weapons, but also different behaviors.

For example, that you become more energetic when you decide to carry out an act of violence, in the digital world it can show itself by writing more posts for example.

What threat does this type of perpetrator pose?

- What makes it difficult is that they act alone, which makes it difficult to detect.

You have to think more broadly to detect this type of perpetrator, partly we may need to be more on the internet but also look at other risk factors that start already in school.

For example, exclusion is a very strong factor in why they commit this type of violence.