A number of police patrols and a police helicopter were on Saturday afternoon at Linnéplatsen in central Gothenburg, where a man was arrested on suspicion of serious weapons crime.
"The helicopter was spotted on the car," says Göran Carlbom, guard officer of the police in the West region.
A house search has been carried out in the car but no weapon has been found.
The arrested man is suspected of serious weapons crime and illegal threats. The man is already known by the police.