The incident took place when Bishambhar Paswan (20) attacked his elder brother's wife Dulawati Devi (34) and her children Amit Paswan (8) and Ragini (1) with a sharp-edged weapon in a fit of rage last night, Brahmpur police station in-charge Dayanand Singh said.
The motive behind the murder was under investigation.
The accused fled from the village after committing the crime, the police officer said.
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