"Circumstances at the scene mean that the police cannot rule out that a crime is behind the man's death and a preliminary investigation into murder is being initiated," the police write on their website.
The police have cordoned off the area and a technical examination is being carried out. A forensic examination will also be carried out to determine the man's cause of death.
According to information provided to Upsala Nya Tidning, an arrest was made earlier on Sunday in a nearby area. The police do not wish to comment on this.
