The father, mother and maternal aunt of two siblings, who were found dead at their Banasree residence in the capital on Monday, are being taken to Dhaka from Jamalpur for interrogation.
A team of Rapid Action Battalion-3 went to Jamalpur and took M Amanullah, his wife Mahfuza Malek and Mahfuza's sister Afroza Malek to Dhaka on Wednesday.
Deceased--Nusrat Jahan Aroni, 14, a Class-VII student of Viqarunnisa Noon School, and her younger brother Alvi Aman, 6, a nursery student of Holy Crescent School, were the children of businessman M Amanullah and Mahfuza Malek.
Physicians of the Forensic Department at Dhaka Medical College Hospital suspect that the two siblings might have been strangled.
No case is filed yet.