The alarm about the shooting came just after half past eight on Tuesday night.
In addition to the bullet holes in the window, sleeves were found at the site.
No person should have been injured.
- We have at least one bullet hole that has been found, then there will be a crime scene investigation soon.
We are waiting for forensic technicians and special search dogs, says Rickard Lundqvist, press spokesperson at the police.
Police: May have been an expired bullet
It is currently unclear whether anyone should have been in the apartment.
- We do not lock ourselves in that shots have been aimed at exactly this apartment, it could just as well be an expired bullet, says Rickard Lundqvis.
Two arrested
A man in his 20s was arrested shortly after nine in the immediate area, on suspicion of attempted murder and aggravated weapon crime.
Less than an hour later, the police announced that another man in his 20s had been arrested, suspected of the same criminal classifications.
During the evening, the police work, among other things, with interrogating any witnesses and collecting surveillance material.
- We do not rule out that there are more shooters, we do not rule out more arrests.
It can be a question of house searches, says Rickard Lundqvist.