Three members of a family, including a mother and two daughters, were murdered and the father was injured in Darwani Bandar Bazar village under Sadar upazila of the district on Friday.
According to the police and locals, Ashiqul Haque Molla fell outside the house with his throat cut around 9am this morning.
The locals rescued him and sent him to the Rangpur Medical College and Hospital.
Locals entered the bedroom of the house and found the dead bodies of Tahura Begum, 35, wife of Ashiqul Haque Molla, daughters Ayesha Akhtar, 8 and Zareen, 5.
Being informed, police rushed to the spot and recovered the bodies from the spot and sent to Nilphamari 250-bed General Hospital morgue, officer-in-charge (OC) of Nilphamari Sadar Police Station Tanvirul Islam said.
The reason behind the incident could not be known yet, said the OC.
Police are investigating the incident, he added.
