At least 17 people have died of alcohol poisoning at a tea estate in Assam’s Golaghat district since Thursday evening, according to The Indian Express. At least 34 persons are undergoing treatment at Jorhat Medical College.

District officials said over 30 people had gathered for a celebration on Thursday night. Four women collapsed and died soon after consuming the country liquor, according to The Hindu. Golaghat Superintendent of Police Pushraj Singh told The Indian Express that multiple people had fallen ill overnight and the toll rose to 17.

“We are not sure if the country liquor was contaminated, but the container in which it was brought appeared to be that of a toxic chemical whose residue could have been mixed with the liquor,” District Deputy Commissioner Dhiren Hazarika told The Hindu.

Deputy Superintendent of Police Partha Protim Saikia said the incident occurred at Salmara Tea Estate. Saikia said among those who died were Dhrupadi Oran, from whose house the tea estate workers got the alcohol, and her son Sanju Oran.

“Since both the mother and the son are dead, we cannot readily say from where they had procured the spurious liquor from,” Singh said. “What made the liquor poisonous can be said only after proper investigation,” he said adding that one possibility could be that they mixed the commonly available methyl alcohol instead of ethyl alcohol.

Assam Excise Minister Parimal Suklabaidya has ordered Additional Excise Commissioner Sanjib Medhi to conduct an inquiry and submit a report within three days, according to All India Radio.

Earlier this month, over 100 people had died after drinking spurious liquor at a village in Haridwar in Uttarakhand.