The three people were all reported to have been seriously injured by the same person, and were taken to hospital after police were informed of the incident shortly after midnight.
The victims were a woman in her 40s and two teenage boys, a police press officer told Aftonbladet. One of the victims was in a very serious condition.
Windows at a building close to the crime scene had been smashed, and an abandoned car was outside the building.
A man in his 50s was detained later on Monday night in a neighbouring village, on suspicion of two counts of attempted murder and one count of aggravated assault.
The investigation continued overnight as police carried out a technical examination and questioned witnesses, and by the morning the police cordons had been removed.
However, police could not comment further on a possible motive behind the attack.
“We are currently working to build an understanding of what happened,” said police officer Mikael Lindh.