Dhaka: The task of investigation into the recent murder of two siblings in the capital’s Banasree area has been transferred to the Detective Branch, reports local news agency.

Deputy Commissioner (media) of Dhaka Metropolitan Police (DMP) Maruf Hossain Sardar on Monday said the case, which was filed over the killing two siblings, was shifted to the Detective Branch on Sunday night for further probe.

Nusrat Jahan Urmi, believed to be14, a seventh grader at Viqarunnisa Noon School, and her younger brother Alvi Aman, around 6years old, a nursery student at Holy Crescent School in Banasree area, were found dead at their apartment on 29 February.

The family first claimed that they died after eating refrigerated Chinese restaurant food.

However, the autopsies conducted on their bodies by the forensic department of Dhaka Medical College Hospital found injury marks on the throat of Urmi and on that of Alvi and his one leg.

Police detained four people—Pintu Das and Shaheen, caretakers of the house, victims’ relative Ferdous, Obaidul Islam, cousin of Mahfuza, and house tutor Sheuli Akter—the following day for questioning them over the death.

Besides, a court asked the Criminal Investigation Department (CID) to conduct chemical tests on the food and water taken by the two siblings and permitted police to conduct DNA tests of the evidence, including pillow-cover, bed-sheet, tissue paper and blanket, collected from the room of the two children.

On 2 March, members of Rapid Action Battalion (RAB) detained Amanullah, Mahfuza and Afroza Malek, the father and mother, and maternal aunt of the two siblings, from Jamalpur district for quizzing them over the mysterious death of the two children.

On 3 March, briefing reporters at the Rab headquarters, its director (media) Mufti Mahmood Khan said during interrogation Mahfuza Malek revealed that she strangulated her daughter and son to death with a scarf as she was worried over their future and education.

Amanullah, father of the two children, filed a case against their mother Mahfuza with Rampura Police Station on 3 March.

A Dhaka court sent Mahfuza on a 5-day police custody on 4 March for questioning over the murder of two siblings.

Earlier in the day, police sought a 10-day custody for Mahfuza.

Inspector (operations) Mustafizur Rahman of Rampura police station, also investigation officer of the case, filed an application before the Metropolitan Magistrate Court seeking permission for taking Mahfuza Malek, the mother of the two kids, on a 10-day custody for interrogating her.