A 29-year-old woman and her daughter died after the mother laced their dinner with poison at their home in Sithalapakkam near Tambaram on Friday.

According to the Pallikaranai police, Uma (29) married Saravanan (33) 13 years ago. The couple’s elder daughter Aarthi (12) was a class VI student, while Abi (10) studies in class II at a government school near their home in Sankarapuram.

Uma is an attendant at Global Hospital and Health City in Perumbakkam, while Saravanan is a tailor who works in Tambaram. The couple reportedly had frequent fights, as Saravanan suspected his wife’s fidelity.

On Friday evening, when the girls returned home from school, they reportedly saw their mother in the company of a stranger at their house. Aarthi chided her mother. Upset over this, Uma mixed poison in the dinner she prepared on Friday, and ate it along with her daughters.

When Saravanan returned home around 10 p.m., he noticed his wife and daughters lying unconscious. With the help of neighbours, he rushed them to Global Hospital. A few hours later, Uma and the Aarthi died, while Abi survived. It is not known what kind of poison Uma used. Police are awaiting the post-mortem report and results of viscera tests.