A team of the army's specialists found no use of explosive substances in the explosion that took place on the 2nd  floor of Shireen Mansion at Science Lab area on Mirpur Road in the capital on Sunday morning. 

The team comprising members of the bomb disposal unit and chemical disaster response team (CDRT) of Bangladesh Army inspected the explosion site in the afternoon and carried out tests. 

 Replying to a question from reporters after completing their inspection,  Bangladesh Army's 57 Engineer Company Commander Major Md. Kaiser Bari said that they initially experimented with explosive detection equipment at the scene. After initial observation, they understood that the explosion was not caused by explosives. If any explosives had been used in the blast, they would have known through the test results, Maj Kaiser Bari said. 

Read: 3 dead, 12 injured as building partially collapses in Dhaka's Science Lab area

He said that after further investigation, it will be known later why the explosion actually took place. 

Replying to another question, Maj Kaiser said, "It could be any kind of explosion. But we need to investigate further to know the actual reason. As we detect explosives with our equipment, so initially we can say that there is no evidence of explosives here. Even no evidence of gunpowder or IED use was found here. The exact cause of the explosion will be known later after further investigation." 

Three people were killed and 12 others injured when the  three-storey building (Shireen Mansion ) partially collapsed following an explosion and subsequent fire at around 10:52 am on Sunday morning. Four units of fire service rushed to the spot and brought the fire under control at around 11:13 a.m.