Four people died on Wednesday after inhaling poisonous gases at a bio-gas plant in Amin village of Haryana’s Kurukshetra district, PTI reported.

The police identified the deceased as Baldev Singh, his sons Devinder and Rupinder, and his cousin Joginder Singh.

Preliminary investigation showed that Baldev Singh had constructed the bio-gas plant, Station House Officer of Adarsh police station Satish Kumar said. On Wednesday, the plant stopped functioning due to a leakage, so Devinder Singh went inside the 10-foot-deep pit to fix it. When he did not come out, his younger brother Rupinder Singh followed him, and when he also did not come out, Baldev Singh went in.

Since none of them came out, Joginder Singh went in to help them out, Kumar said. However, he also did not return. A farmer from the neighbourhood finally found them and took them to a hospital but doctors declared them dead on arrival.

“We have registered a case under relevant provisions of the law and sent the bodies for a postmortem examination,” Kumar said.

Villagers said the agriculture department must warn them of such risks when it persuades them to set up bio-plants, the news agency reported.