When the emergency services arrived at the scene, a corridor at the school was filled with smoke and it turned out that someone had thrown a banger into the corridor.

- A banger is like a bigger firecracker.

Loud noise but very little explosive effect, hence the name says Pedher Helmer, officer on duty at the rescue service Östergötland.

The emergency services opened the windows and aired out, then the students were welcome back into the school.

The police have just arrived at the scene.