All four members of a family found dead at their home in Rangpur city on Saturday were strangled to death, and the disfigurement of their faces was caused by natural decomposition rather than a chemical substance, forensic experts revealed on Monday.

The clarification was provided by Dr. Babul Kumar Biswas, an assistant professor at the forensic medicine department of Rangpur Medical College Hospital, following his completion of the autopsies.

The victims have been identified as Ganapati Chakraborty alias Jewel (65), a former teacher at Rangpur Zilla School; his wife Pritilata Chakraborty (50); their daughter Parthi Chakraborty Agami (25); and their son Priyam Chakraborty Ayush (12), a Class-V student at Rangpur Zilla School.

Dr. Babul confirmed that there were no signs of chemical burns on the bodies.

"When a body decomposes, exposed areas outside the clothing can sometimes turn dark. This is part of the decomposition process," he told a local media over the phone on Monday afternoon.

He explained that the dark appearance of the victims' faces was caused by changes in blood and body tissues during decomposition and not by any chemical treatment.

"The faces did look dark but there were no signs of chemical burns," he added, noting that while there were some minor injuries that may have resulted from a struggle, nothing else significant was found.

The medical findings address initial speculations raised by investigators.

Previously, Sumit Chowdhury, Rangpur CID Superintendent of Police (in-charge), stated on Sunday that investigators suspected possible chemical use because of the severely disfigured condition of the faces and the presence of liquid nearby.

Rangpur Metropolitan Police Commissioner Mohammad Abdul Mabud disclosed the details of the gruesome murders during a press conference at his office on Monday morning.

According to police, the family members were killed after they allegedly objected to two young men taking Yaba on the rooftop of their house.

Police arrested two neighbours, Siddhartha Das (23) and Mugdha Das (19) on Saturday night in connection with the killings.

The pair were produced before the Rangpur Chief Metropolitan Magistrate Court-2 around 11:30 pm on Sunday, where their confessional statements were recorded under Section 164 of the Code of Criminal Procedure before Metropolitan Magistrate Rafiq-ul Islam.

They were subsequently sent to jail.

Milon Chakraborty, Inspector (Investigation) of Kotwali Police Station and the investigating officer of the case, confirmed the court proceedings but noted that the specific details of the confessional statements were not disclosed in the interest of the ongoing investigation.

The legal proceedings were formally initiated on Sunday when Gopinath Chakraborty, the elder brother of Ganapati Chakraborty, filed a murder case with the Rangpur Kotwali Police Station.

With Inputs from UNB