Police named the victims as Anwarul Islam, 45, his wife Jahanara Begum, 35, the couple's 10-year-old son Jahid Hasan Soad.
The incident took place at Saraigachhi in Naogaon's Porsha upazila on Thursday morning.
Porsha police station's Officer-in-Charge Mosadul Haque said, Anwarul got tangled in an electric wire near his house in the morning.
The other two were electrocuted when they tried to save him.


