A young man has been released from a so-called SiS home outside Vänersborg.
According to the police, three younger men must have gone to the youth home in a taxi and then threatened the staff and thus released a man in his 18s.
The men are not said to have shown any weapons, but threatened to "shoot the staff".
Police arrived quickly at the scene and were able to arrest all four people.
They are suspected of unlawful threats, threats against an official and additional criminal classifications may be added.