A case has been filed against unidentified persons over the killing of four family members at their home in Khalsi village of Helatala union in Satkhira's Kalaroa.
"The case was registered with Kalaroa police station on Thursday evening where the mother-in-law of deceased, Shahinur Rahman became the plaintiff," Officer-in-Charge (OC) of Kalaroa police station, Haran Chandra Pal said.
"There is no doubt that it was a premeditated murder. All the units of law enforcement including the Criminal Investigation Department (CID) of police are working to unravel the mystery of the murder," he added.
Earlier, on Thursday morning, Shahinur's younger brother Raihanul Islam discovered the bodies on Thursday morning.
The deceased are- Shahinur Rahman, 40, his wife Sabina Khatun, 30, son Siam Hossain Mahi, 9 and daughter Tasnim, 6.
According to Raihanul Islam, younger brother of the deceased Shahinur Rahman, they were six people in the family, including him and his mother. On the night of the incident their mother was not at home.
"Early in the morning, I heard the sound of groaning while I was sleeping next door," Raihanul said, adding that, "When I opened the door, which was locked from the outside, the kids were still alive and shortly breathed their last."