Mizan Sheikh, Meherunnesa Sharna alias Afrin alias Annafi, Suraiya Akhter alias Keya and Fariya Binte Mim were arrested in separate drives conducted by the Detective Branch (DB) of Dhaka Metropolitan Police (DMP) at Badda and Hazaribagh in the city on Wednesday night.
Briefing reporters at the DMP Media Centre on Thursday afternoon, DMP Additional Commissioner (DB) Abdul Baten said detectives earlier arrested Rahmatullah from the capital's Uttara area on July 10 suspecting his involvement in the killing of the SB official.
During interrogation, Rahmatullah disclosed the names of the four arrestees and based on his information, they were arrested from Badda and Hazaribagh, he said.
Earlier on July 10, the charred body of Mamun who went missing from his brother’s house at Sabujbagh on July 8 was recovered from a forest in Rayerdia area of Kaliganj upazila in Gazipur district.
Rahmatullah along with Inspector Mamun went to a flat of Banani in the name of celebrating the birthday of a model.
The four arrestees beat Mamun to death and took the body to Ulukhula of Gazipur where they left the body after set it on fire pouring petrol.
A murder case was filed with Banani Police Station over the incident.