An elderly woman was allegedly killed inside her residence at Isojoki in South Ostrobothnia.
Relatives of the 72-year-old found the body on Sunday, police said, adding that the woman died a violent death.
Police arrested a man of 47 years, who lived in the same house with the woman in connection with the murder.
According to the police, the homicide appears to have occurred on Friday afternoon.
The suspect left the scene after the deed by the victim's car. Later that day, he drove into the rails along the bridge in Teuva and was transported to the Seinäjoki central hospital.
According to police, the man is recovering from his injuries.