CHENNAI: A 33-year-old woman killed her two children by giving them poisoned milk after planning to elope with her boyfriend.Police have detained the woman’s boyfriend, Sundaram, in connection with the murder of the two children. Their mother, identified as Abirami , is absconding.Police said Sundaram works at a biryani shop near Abirami’s house on Agasthiar Koil Street in Kundrathur . During questioning, Sundaram told police that he had a relationship with the woman. The two had planned to leave the city.“We are not sure about the motive behind the murder of the two children. We can deduce that after arresting Abirami,” said an investigating officer. Police teams have been assigned to trace her.“Abirami had parked her scooter at the Koyambedu bus terminus and may have boarded a bus,” the officer said adding that police have collected CCTV camera footage to trace her.Based on a complaint from Abirami’s husband Vijay, 35, the Kundrathur police have registered a case. The couple got married eight years ago and had two kids Ajai, seven, and Karunika, five.Police said on Friday night, Vijay had called his wife to inform that he would not be able to return home due to work. He came back at 7am on Saturday and saw the house locked. Vijay tried calling Abirami but her phone was switched off. He broke open the door and found his children lying on the bed with their mouths foaming. Vijay called for an ambulance which took the children to a private hospital nearby where doctors pronounced them dead. A policeman said by staying away for work Vijay might have had a narrow escape as he too would have taken the milk.