Among the detainees, Kamal was a close associate of “Kailya” Babu, the prime accused in the murder case, said Rabiul Karim, operations officer of Rab-3.
The other four–Raju, 20, Opu, 30, Sohel Khan, 28, and Billal, 24, are accused in the case filed by Kala Chan, brother of one of the victims Ranu, with Ramna Police Station.
On August 28, criminals gunned down Mohammad Munna, 18, Billal Hossain, 20, and Ranu, 28, and injured Hridoy, 20, another brother of Ranu, in a house at Sonalibagh over extortion and land dispute.
In the case, Chan accused 15 people including “Kailya” Babu who was killed in a “gunfight” with detectives on September 15.
Earlier, eight persons were arrested in connection with the murders.