Police has said four masked gunmen took part in the killing mission in Banani, but failed to make an arrest in connection with the murder of a businessman.
They also say they have information about the killers and the hunt is on to capture the suspects.
Manpower agent Md Siddique Hossain was gunned down in his office at Banani in the capital on Tuesday.
The victim's family, however, cannot say anything about the motive behind the murder either.
Referring to witness accounts and CCTV footage, police say four masked assailants took part in the killing at Messrs S Munshi Overseas on Tuesday night.
Siddique's wife Jyotsna Begum started a case against four unidentified people on Wednesday evening,said Banani Police Station Inspector Abdul Matin.
The attackers carrying gun entered Siddique's office at Road No. 4 around 8:30pm and fled after spraying bullets on four people, including Siddique.
Siddique died while undergoing treatment at the United Hospital. The three others, 'Mukhles', 'Mostaque' and 'Parvez', employees of the firm, were also admitted to the hospital.
"Four masked people are seen shooting at the victims in footage. Their image is clear in the footage and we have information on them," the inspector said.
"We hope to crack the case very soon," he added.
Dhaka Metropolitan Police Deputy Commissioner Mostaque Ahmed suspects it is a premeditated murder.
"We are yet to know the motive. Every angle -- family and business -- is being investigated. Initially, it seems to be a premeditated murder," he said.
After visiting the scene on Wednesday, DMP Joint Commissioner Krishnapada Roy said they were investigating the case with priority.
Dhaka Medical College forensic department chief Sohel Mahmud said after the post-mortem examination that a bullet entered Siddique's chest through the left side and stuck on the right side. Another shot ripped through his hand.
Siddique's brother Abdul Latif could not say why the assailants killed his brother.
'Zafar', an employee of Siddique's firm, was present when the attack was carried out.
He said four masked men entered the office and asked where the cashbox was.
"When we said we keep money in a bank, they rebuked us. One of them pulled the trigger, but the weapon did not fire. Then they fired several shots indiscriminately," he said.
Peon Ali Hossain said he was leaving the room when one of the miscreants entered.
"One of them wielding a gun hushed me and shot at sir. I remember hearing the shot. Later, I saw sir lying under the chair. When I tried to take sir out, I found the door locked from outside," he said.
Security worker Alabinuz Bazi was outside the office during the incident, says a bdnews24.com
He said the assailants came like other clients often come to the office.
"I didn't know what was happening inside. I didn't even hear the shots. I opened the door when the others were thumping the door from inside," he said.
Siddique's son-in-law Abu Hanif, who works as an accountant of the firm, said he was not at the office at the time of incident.
He said he did not know whether his father-in-law had any dispute with anybody.
Siddique, the father of two daughters and a son, resided in Uttara. He hails from Tangail.