Local people found smoke emitting from the house of Jayanti Sahoo last night.
After fire brigade personnel doused the blaze, bodies of Jayanti (28), her 6-year-old son Asish and 7-month-old girl Saishradha were discovered, the police said.
Her husband Ananta Sahoo was detained.
The police said Ananta used to threaten his wife that he would marry another girl and that's why the needle of suspicion is pointed towards him.
Jayanti's father Suryamani Sahoo lodged an FIR alleging that his daughter and two grand children were killed by his son-in-law.
