A policeman was shot dead by one of his fellow colleagues while performing duty in the capital's Baridhara late on Saturday night.
The incident took place in front of the Palestinian Embassy in Dhaka.
The victim policeman was identified as Monirul.
Mazarul Islam, officer-in-charge (OC) of Gulshan Police Station, said another pedestrian was injured in the incident.
"We heard the news and are heading towards the spot," the OC said, adding that the details will be known later.
Meanwhile, the CCTV footage shows altercation leading to constable Kawsar shooting at Monirul inside diplomatic zone.
The hazy and noisy CCTV footage obtained from the Palestinian Embassy in Dhaka initially showed what looked like just two colleagues in uniform arguing about something.
The altercation did seem intense, but nowhere close to one where someone would resort to killing the other.
But that is exactly what happened last night. The location? A highly secured diplomatic zone.
The person involved in the killing is no other than the same person who was supposed to stop something like this from happening inside such a highly secured area in the capital.
Around 11:40pm last night, a police constable named Md Monirul, 27, was shot dead by another constable named Kawsar Ali, 41, in the Gulshan diplomatic area.
What the CCTV footage shows
The CCTV footage recording the whole thing shows Monirul and Kawsar in a heated argument.
At one point, Monirul showed Kawsar what appeared to be a duty notebook.
Almost instantly, Kawsar started shooting at him. Monirul immediately fell to the road. But he was not done yet.
Kawsar was then seen firing a few more rounds directly at Monirul as he was lying on the road.
As Monirul's body became motionless, Kawsar calmly took his gun and moved away a few steps.
Later, he squatted down and shouted at the passersby and a vehicle. He even pointed an SMT gun at the vehicle. The footage ends.
Kh Mahid Uddin, additional police commissioner (crime and operation) of Dhaka Metropolitan Police (DMP), at a press conference on Sunday said, "Initially, there seemed to be an argument between the two police constables over some issue,"
"We will be able to provide more details after a full interrogation of the accused constable," he added.
Mahid Uddin also said the incident might have occurred due to a momentary escalation of tension.
"We spoke with the accused constable Kawsar. No information regarding any prior conflict was found," he added.
Meanwhile, a case has been filed with Gulshan Police Station over last night's incident.
Rifat Rahman Shamim, deputy police commissioner (DC) of Gulshan division of Dhaka Metropolitan Police (DMP), said Mahbubul Alam, Monirul's brother, filed the case today, naming constable Kawsar as the accused.
Police also presented the arrested constable Kawsar before the court today with the investigating officer seeking a ten-day remand plea.
"However, the court has yet to issue any directives," said Rifat.
He added that CCTV footage obtained from the Palestine Embassy is now the primary evidence of the case.
Besides, a Dhaka court on Sunday granted the police a seven-day remand for constable Kawsar Ali, who reportedly shot another constable in the Baridhara diplomatic zone in Gulshan late Saturday.
Dhaka Metropolitan Magistrate Md Shakil Ahammad granted the remand following a hearing on a 10-day remand plea from police.
