The package was opened inside an apartment in a multi-family house. According to the police, it may be some kind of cartridge that was triggered when it was opened.
The person who opened the package has sustained minor facial injuries, says police spokesperson Ola Österling.
The alarm came in at around 12:30 on Sunday. In the evening, the police reported that a man had been arrested in connection with a search of the premises.
After the investigative measures taken directly after the incident, one name emerged and became interesting, says police spokesperson Daniel Wikdahl.
The suspect is in his 70s. The man has been charged with attempted aggravated assault and serious violations of the law on flammable and explosive goods.
The person who sustained minor injuries was taken care of by ambulance personnel on site, but did not need to go to the hospital.
