Abhishek Das and daughter Karpurika. Pictures by Amit Datta

A homemaker on Thursday poured toilet-cleaning acid into her two-and-a-half-year-old daughter’s mouth and strangulated her to make sure she was dead before trying to kill herself.

Admitted to RG Kar Medical College and Hospital with multiple burns, Soma Das, 28, mumbled to police that she was “repentant” for killing her daughter, but would not say why she did it.

The police believe Soma took the step because she suspected her husband Abhishek, a customer care executive in the call centre of a private bank, of having an extra-marital relationship.

The Das’s neighbours in their Belghoria apartment, Northern Plaza, were the first to know of the incident. “It was around 9 in the morning when we heard Soma crying for help and came out of our flat to see her in flames. The door to their flat was open but the grille was locked,” said S. Biswas, who stays next door.

The neighbours broke open the lock and first took Soma and daughter Karpurika to Sagar Dutta Hospital in Belghoria, where the little girl was declared “brought dead”. Soma was later shifted to RG Kar.

Abhishek said he was unable to make sense of the tragedy. On the police’s suspicion that he was the reason for Soma acting the way she did, the bank employee said he and his wife quarrelled sometimes, but it was never serious enough to trigger murder and attempted suicide.

“When I brought my wife and daughter back from my in-laws’ Golf Green residence this week, we were very happy. Even when I left home in the morning, I had no idea something was wrong,” he said.

Soma’s family filed a complaint at Belghoria police station on Thursday evening, accusing Abhishek of torturing her.

Abhishek’s father Kalyan Das, a retired banker who lives close to Northern Plaza, contested the allegation. “My daughter in-law never complained to me about torture,” he said. Abhishek and Soma had married three years ago against the wishes of their parents.