Morgue sources said SI Mizanur, who was found dead in house No. 6 on road No. 116 of Gulshan-2, was strangled to death and bore several marks of injury on his eyes and head.

Khan Mohammad Sirajul Islam, officer-in-charge (OC) of Gulshan PS, told The Daily Star that they are not sure yet who killed the SI and why. Different teams of Rapid Action Battalion (Rab) and the Detective Branch of police are investigating the matter, he said.

The police filed a murder case.

The police suspected that the people who came by a white microbus to pick up Mizanur from Gulshan PS on Tuesday night committed the "pre-planned" murder.

SI Mizanur had been investigating 12-15 cases, a few of them sensitive, and his murder may have links with them, the police said, adding that they did not find Mizanur's mobile phone and revolver at the spot where is was found.

Mizanur's namaz-e-janaza was held at the Rajarbagh Police Line mosque after Zohr prayers yesterday. He was later buried at his village home in Tangail.

Mizanur joined the police force in 1994 and was posted at the Gulshan PS eight months ago.

His family members demanded immediate arrest and exemplary punishment to the criminals involved with the murder.