Police recovered the throat-slit bodies of a woman and her daughter, son from Tea Garden area at Fatehepur under Goainghat upazila of Sylhet on Wednesday morning.
The deceased were identified as Aleya Begum, 35, wife of Hijbur Rahman and their son Mizan, 8, 5-year-old daughter Tanisha, hailing from Binnakandi Fulertal area of the upazila.
Police also rescued Hijbur Rahman in critical condition.
Sylhet Additional Deputy Superintendent of Police (Headquarters and Media) Lutfar Rahman said that the miscreants wanted to kill four members of the same family.
However, neither the motive of the murder nor the identities of the killers could be known yet, he said.