A homemaker and her minor son residing at the Uttarayon township on the outskirts of Siliguri were found dead at their residence on Thursday.

Her daughter and husband, who have also fallen ill, are under treatment. The Siliguri Metropolitan Police have initiated a probe and waiting for the post-mortem reports.

Sources said that Sujit Das, a businessman in his mid-forties, resided at a house in the E zone of the township on rent with his wife Tithi, 38, daughter Tejal, 18, and son Tejas, 8.

On Wednesday night, the family had their dinner after which Sujit left on an errand. Tejal, who studies in Bangalore, was here to spend the holidays with her family.

“On Thursday morning, she was feeling unwell due to suspected food poisoning and woke up. She saw her mother lying in the washroom and her brother lying on the bed. She felt it unusual and called up Tanmoy Sarkar, a relative who stays in the same property,” said a source.

Tanmoy reached the house and he and Tejal took Tithi and Tejas to a private nursing home in Matigara. The on-duty doctors there pronounced Tithi and Tejas dead.

The doctors examined Tejal and said she needed to be admitted to the nursing home for treatment. Soon, Sujit reached the nursing home. He fell ill from shock and was admitted to the same nursing home.

Police were informed and a team from the Matigara police station reached the nursing home. The bodies were sent to North Bengal Medical College & Hospital for post-mortem.

Police officers also went to the house and started an investigation. During the preliminary probe, they found a coal oven in one of the rooms. The washroom was dirty.

“We have registered a case of two unnatural deaths. We can comment on the cause of these deaths only after we get the post-mortem reports,” said BC Thakur, the deputy commissioner (west) of the Siliguri Metropolitan Police.

S.K. Mitra, the township's estate manager, said he did not know anything about the Das family. "All we know is that the owner of the house rented his property to Sujit Das where he was staying with his family," he said, adding he did not know when the family came to stay here.