Spokesperson of the secular platform Imran H Sarker made the demand while speaking at a sit-in demonstration in front of the National Museum on Friday.
The programme was organised to press for the quick execution of death verdict of war criminal Jamaat-e-Islami leader Mohammad Kamaruzzaman.
Extremist militants are blamed for the Feb 26 murder of Avijit, an advocate of secularism and free thinking.
“We will have to arrest and punish quickly those involved in the murder of Avijit and also expedite war crimes trial in order to eliminate these terrorists, militants.”
He said, with the start of the trial of suspected war criminals after 43 years of independence, Bangladesh could shake off, to a certain extent, from the culture of impunity.