Police found the bodies of three persons and a critically injured five-year-old in a house in Dighar union under Ghatail upazila of Tangail on Saturday morning.
The deceased are Sumi Begum, 30, wife of Saudi expat Jayen Uddin, her mother-in-law Jamela Begum, 65, and Shahjalal, 25, a resident of Kalihati upazila.
Meanwhile, the authorities sent Sumi’s injured child to the hospital for urgent medical attention.
The deaths likely took place sometime on Friday night, according to Dighar Union Parishad Chairman Abul Kalam Azad Mamun.
Ghatail police station OC Azharul Islam said it was not immediately clear whether they were murders or suicide.
Police would disclose further details after investigation, he added.
