We are working intensively to create a situation picture, secure the crime scene and search for possible perpetrators, says the police's press spokesperson Mats Pettersson.
At midnight, the police confirm that one person has been arrested as a suspect in connection with the incident, which Södermanlands Nyheter has reported on.
Several people alerted the police to a loud bang at around 21:30 on Tuesday. The area has residential buildings, shops, and restaurants.
This has happened at a place and at a time when there is a good opportunity for people to have seen the whole or parts of the incident, says Mats Pettersson.
Late on Monday evening, a dangerous object was found between two residential buildings in Stenkulla. According to Södermanlands Nyheter, it was a hand grenade that was secured and neutralized by the police.
Tuesday evening's explosion is being investigated as general endangerment and the hand grenade find as attempted general endangerment.
