The deceased were identified as Khaleda Akter, 22, wife of Abu Bakar Siddique, and her one-year-old boy Ismail Hossain.
Alamgir Hossain, officer-in-charge of Daudkandi Police Station, said Abu Bakar of Kachua Upazila in Chandpur district had developed a love relation with Khaleda, daughter of Abdul Barek of Mirakhola village in Chandina Upazila while working at Shahidnagar Industries Limited.
Later, they got married and used to live at Bhagalpur village after leaving their job at the factory.
Getting the room of the Khaleda was locked from inside, locals informed the matter to police who recovered the bodies of the woman and her son, breaking open the door in the morning.
The bodies were sent to Cumilla Medical College Hospital morgue for autopsy, said the OC.
Police suspected that Khaleda at first feed food laced with poison to her child and then killed herself in absence of her husband Abu Bakar, the OC added.