The newly elected mayor of a town in western Germany was in a critical condition after being found with multiple stab wounds on Tuesday, authorities said.
Iris Stalzer, 57, dragged herself back into her house after being stabbed around midday, broadcaster WDR reported. Bild newspaper said she had stab wounds to her neck and abdomen.
Prosecutors and police said in a joint statement their inquiry was looking into every possibility and said: "Close family involvement cannot be ruled out at the present time."
Her son and daughter, aged 15 and 17, had been taken in for questioning. Stalzer was airlifted to hospital and was still in intensive care.
The attack comes after a region-wide election campaign that politicians in North Rhine-Westphalia, Germany's largest state, said was distinguished by the viciousness and rawness of its tone.
Stalzer, a Social Democrat, is due to take office in November after being elected mayor of Herdecke in the Ruhr region.
CASE STIRS MEMORIES OF OTHER ATTACKS ON POLITICIANS
A study published in May found 60% of politicians in Germany had experienced violence at least once, with one in five saying it had made them more reluctant to appear in public.
Even though the motive was unclear, the case raised memories of the 2019 murder of conservative local government president Walter Luebcke, a supporter of then chancellor Angela Merkel's refugee policy, who was shot by a far-right activist as he smoked a late-night cigarette on his terrace at home.
Four years before that, Henriette Reker was stabbed by a right-wing extremist the day before she was elected mayor of Cologne. She made a full recovery and is due to leave office later this year.