Three women including a local politician and two journalists were shot dead with a rifle in front of a restaurant in the small Finnish town of Imatra around midnight, police said on Sunday.
A 23-year-old local man with a criminal record was detained at the scene, the Southeastern Finland Police Department said.
It said the motive for the killings remained unclear.
“At the moment, it looks like the victims were chosen at random,” Detective Inspector Saku Tielinen told a news conference.
Victim Tiina Wilen-Jappinen was chairwoman of Imatra City Council while the other two women were journalists, the police said.