It was just after 6pm on Saturday that the police received the alarm about a big fight on Mårtenstorget.
When the police got there, the people disappeared in different directions, but two injured people remained at the scene.
A man in his 20s was taken to hospital by ambulance.
He had suffered stab or cut injuries and it was not judged to be life-threatening.
A man under the age of 18 was also injured, but did not need to be taken to hospital.
- It is hard work.
None of them want to participate, which makes it more difficult for us to find out what has happened, says Rickard Lundqvist, press spokesperson at the police.
How do you proceed with the case?
- We have spoken to witnesses and there may be more witness statements that we have to go through.
Then we document the scene and see if there are surveillance cameras or if someone filmed the fight.
No suspects have been arrested.
The police are classifying the incident as serious assault.