"It seems that several families have got into a fight during a student celebration. A boy and a man have suffered serious head injuries, says Peter Adlersson, police spokesman.
Both the man and the teenage boy have been taken to hospital by ambulance.
"It's a messy case with many people involved. We are talking to both witnesses on site and involved to try to get a clearer picture of what happened.
Two arrested
Two men have been arrested by the police and a car has been seized.
"Two cars managed to leave the scene before we arrived," says Peter Adlersson.
Several more people are slightly injured.
The police classify the incident as aggravated assault.
Woman beaten
Just half an hour later, the police were alerted to the same address, where there had again been a fight. At that time, several people had entered a residence and hit a woman in the head with a hammer. She has been taken to hospital but according to police has no life-threatening injuries.
The second case is also currently being investigated as aggravated assault. Parts of the home are cordoned off for technical examination.