Inspector Mamun Islam Khan was killed by a gang of blackmailers, detectives said yesterday.
Quoting suspect Rahmat Ullah, detectives said Mamun was killed on Sunday in a party at a Banani flat where they had gone together. Rahmat also said he was a friend of Mamun.
At one stage, several other suspects attempted to blackmail Rahmat by taking revealing pictures of him with some women present at the party, a number of officers told The Daily Star, wishing anonymity.
As Rahmat and Mamun tried to protest, the suspects started to beat them up.
When Mamun revealed that he was a police officer, the suspects beaten him to death, officers said.
Rahmat and the other suspects later dumped Mamun's body in Gazipur.
Rahmat, 35, who was arrested on Tuesday, is being interrogated by Detective Branch of police. He is on a seven-day remand.
He has given the names of 10-12 other suspects involved in the murder.
He told detectives that the gang often blackmailed its victims. Rahmat also told police that the gang rented 7-8 flats in different parts of the capital to conduct illegal activities. The flats were rented by suspects named Nazrul Islam and Sheikh Hridoy alias Papon alias Rabiul.
Inspector Mamun's elder brother Jahangir Alam Khan told The Daily Star yesterday that Mamun went to the Banani flat on Sunday evening from his Bashabo house after getting a phone call from his friend.
After killing Mamun, the gang members put his body in a sack and took it to Gazipur in Rahmat's car. They dumped the body in a bush in an isolated area.
The suspects poured petrol on the body and burnt it before dumping it, police quoted Rahmat as saying.
Detectives recovered the body on Tuesday.
Jahangir said Mamun was posted to different police stations in Dhaka and Chittagong since 2006. Mamun was buried at Shahjahanpur graveyard on Wednesday.
Deputy Commissioner (East) of Detective Branch Khandker Nurun Nabi said he hoped to arrest more suspects in a couple of days.
Police sources told The Daily Star that the flat where the murder took place was rented for Tk 45,000 a month.