Rapid Action Battalion (RAB) arrested four persons, including former lawmaker and Islami Democratic Party Chairman MA Awal, in a case filed for the hacking of a man to death recently in the capital's Pallabi area.
Shahin Uddin, 33, was hacked to death in front of his 7-year-old child in broad daylight on Sunday.
The others arrested are Hassan, Jahurul Islam Babu, and Sumon Bepari.
Of the four arrested, RAB arrested three while police arrested one.
In a media briefing on Thursday, Commander Khandakar-Al-Main, director of RAB's media wing, said Shahin was killed in a land business dispute. MA Awal is the prime accused and the principal planner of the murder. RAB arrested him from Bhairab.
At least 12 miscreants took part in the killing mission, he said.
After the murder, Shahin's wife Aklima Begum filed a murder case accusing 20 people including former Lakshmipur-1 lawmaker, MA Awal.