At half past twelve on Friday evening, the police received a call about loud bangs.
At the scene, it was established that a shooting had taken place when shell casings were found.
The police were on site during the night with several resources to search the area with a helicopter and a dog, but no one was found injured.
During Sunday morning, however, the police were able to confirm that a person was found seriously injured and was taken to hospital by ambulance.
The police are working to see what connection there is between the shooting in Sollentuna and the injured man.
Two people have been arrested on suspicion of serious weapons offenses and attempted murder, and a number of people have been taken in for questioning.
The police have also started a technical investigation at the scene.