The alarm came at 19 o'clock on Wednesday evening, when the police received a call about an injured person at an address in Piteå municipality.
When the police patrol arrived at the scene, they found a dead person.
The place is cordoned off
What injuries the person had is unclear.
The police have launched a preliminary investigation into murder or manslaughter and at least one person has been detained.
- I can not say much more than that at the moment.
The site is cordoned off and we have taken several investigative measures, says Casey Causevic, RLC officer in the police region North.
Relatives have been notified.