Witnesses said that Budu got electrocuted when he came in contact with an electric wire while cleaning his backyard in the morning.
The wire was connected to an illegally established temporary electric line for an adjacent Durga Puja temple, they added.
Palash, Khitish and four others got electrocuted too when they tried to save Budu.
The three died on the way while they were being taken to upazila health complex.
Among the survivors, a man named Rubel Chandra Bhuiyan is still undergoing treatment at the medical facility while the remaining two were sent home after giving first aid, said Sherpur police station officer in charge Shahidul Islam.