It was medical staff who contacted the police after a woman was taken to hospital by ambulance.
It was then unclear what had happened, but it could not be ruled out that the woman had been the victim of a crime.
- I can not go into what injuries she has.
The reason is that a preliminary investigation is underway now and the prosecutor has taken over the case, says Björn Öberg, the police's spokesperson for Region East.
The suspicions were strengthened
After the police work during the night, the suspicions led to someone causing her injuries and during the night towards Thursday, a close man was arrested for the woman.
The man in his 65s was later arrested following a decision by prosecutors.
He is suspected of attempted murder.
According to the police, the man and the woman have a relationship.
The police are now working on a crime scene investigation and are holding interrogations in the case.