Four members of a Nepalese family were found dead at a poultry farm in Bengaluru rural district of Karnataka on Sunday morning, police officers said, adding that the exact cause of the deaths could not be ascertained.

According to the police, the family worked at Holeyarahalli, near Doddabelavangala in Doddaballapur taluk. The deceased have been identified as Kale Sarera (60), Lakshmi Sarera (50), Usha Sarera (40), and Pool Sarera (16). “The family joined for work just 10 days back at the poultry farm on graveyard road,” a police officer said, requesting anonymity.

All four were found dead on Sunday morning. The incident came to light when the poultry farm owner, Mohan, called the workers in the morning, but none answered, the officer said.

The owner then contacted the relatives of the deceased, who were working at the neighbouring poultry farm, the officer said.

“The cause of death of the four family members remains unknown,” the officer said.

Initial findings suggest the family members may have used a charcoal heater to keep warm and ward off mosquitoes on the rainy night, police said. Closing the shed door might have led to a buildup of smoke from the burning charcoal, resulting in a lack of oxygen and increased carbon monoxide levels, which could have resulted to their deaths, officers added.

“When checked the house, there was some smoke inside the room. The Forensic Science Laboratory team (FSL) has been called in to determine the actual cause of death of the four individuals,” Bengaluru rural district SP Mallikarjuna Baladandi said.

He ruled out any foul play in the incident saying the door and windows were locked from inside the shed and there was no sign of any kind of poisonous substance inside. “The FSL team also confirmed initially that the deaths were due to asphyxiation,” he said, adding they are waiting for the autopsy report.

A case has been registered at Doddabelavangala police station under Criminal Procedure Code 174 and further investigation is on. The bodies were shifted to Victoria hospital in Bengaluru for autopsy and handed over to their relatives on Sunday.