The deceased were identified as Shikha Akter, 29, her son Arafat Islam Alvi, 9 and daughter Saifa Akter, 2.
Yasmin Khatun, Superintendent of Police of Manikganj, said Shikha might have poisoned her children before taking her own life by swallowing the same poison following a family dispute.
She said Shikha was the second wife of Malaysia expatriate Dewan Shahin Ahmed and Alvi was her son from her first marriage while Saifa was Shahin’s daughter.
Locals said neighbours became suspicious after repeated knocks on their door went unanswered.
Later, the house owner informed police who broke into the house and found the bodies inside, reports UNB.
Police also recovered an empty container from the scene.
OC of Manikganj Sadar Police Station SM Aman Ullah said the bodies were sent to the hospital morgue for autopsy.