An explosion occurred at a villa on Tjörn, Sweden, during the night, severely damaging the outdoor patio.
The incident happened almost simultaneously with another explosion in a residential building in Malmö, initially raising suspicion of a connection.
However, authorities have since ruled out this possibility.
The police are investigating potential links to gang activity in Hisingen, Gothenburg.
No casualties were reported, but the patio door and parts of the patio were destroyed.
In a separate event, a widespread train driver strike in Germany has halted major parts of the country's train services.
The strike, part of an ongoing wage negotiation, is expected to last until Friday evening.
The Swedish company Green Cargo has had to suspend its freight traffic due to the strike, affecting the import and export of goods, and potentially causing significant disruptions in Sweden.