Detective Branch of Police arrested six suspects in connection with the killing of Bangladesh Chhatra League (BCL) leader Fazlul Huq alias Babu from different parts of the capital and Kushtia Monday night.
They also seized three firearms, 23 rounds of bullets and two motorbikes from their possessions.
The arrestees are Golam Mahdin alias Titu, 30, his younger brother Golam Kader alias Rummon, 26, Shahriar Kabir alias Saimon, 27, Md Kamruzzaman Ahmed alias Azad, 38, Mizanur Rahman alias Swadhin, 41, and Sohrab Hossain alias Swapan, 42.
On Apr 21, Babu, president of BCL's Ward No 90 unit, was shot dead by criminals in the capital's East Kazipara.
Soon after the murder, Babu's father had accused Titu of killing his son following a dispute over a piece of land owned by an uncle of the deceased.
DB Additional Deputy Commissioner Mashiur Rahman said among the detainees Titu and Saimon had shot Babu while the rest four accompanied them in the murder.
"The firearms seized from the detainees were used in the killing and the motorbikes were used for fleeing the crime scene," he said.
DB officials at a briefing at the Media Centre of Dhaka Metropolitan Police said all the arrestees admitted their involvement in the murder.
The detainees killed Babu for three reasons, including dispute over a piece of land; establishing supremacy over controlling jhut (garment wastage) business; a personal enmity between Babu and Titu, they said.
The enmity between Titu and Babu was ensured as Babu filed a theft case against Titu with Kafrul Police Station, and police arrested him in the case.