Several police patrols went to the scene and cordoned off a large area.
The police caught witnesses, secured tracks and searched for a perpetrator who had left the crime scene, police spokesman Björn Öberg states.
The initial alarm came at 20.42.
Barely an hour later, a suspected perpetrator could be arrested.
The police have not landed in a criminal classification, but according to Öberg, there will probably be attempted murders.
The person who has been injured must not have received life-threatening injuries according to information from the health service.