Bodies of the 27-year-old woman along with her seven-month-old baby were found last night near Bhalukpung.
It was suspected that the killer had tried to rape the woman and killed her after she tried to save herself by coming out of her house along with the infant, the sources said.
One person was arrested in this connection.
Village headman Diken Rabha said the mother of three children stayed alone as her husband works as a labourer at Seppa in Arunachal Pradesh.