Bansidhar Madhial, who had performed a puja late on Friday night, allegedly hit and killed his sister Katina Nayak (35) and niece Rekha (10) with a blunt object.

They died on the spot, police said. Madhial's son Jagan (13), critically injured in the incident, died in a nearby hospital in Betanati after being admitted there.

Madhial, a clerk in a government office, has been taken into custody and further proceedings are underway, police said.

Though the reason behind the killing was yet to be ascertained, preliminary findings indicated it could be a case of human sacrifice as the accused had been worshipping during late hours of night for the last couple of days, police said.