He says international sanctions on top junta officials bar Bangladesh from wider engagement with the Myanmar military
They staged the demonstration in front of the district administration office and stayed there for one and a half hours on Tuesday.
A committee formed to protest the alleged killing also joined the programme.
The activists have issued a memo to the home minister asking penalty for the 'murderers'.
They have also asked for compensation for Romel's family.
Army detained Romel Chakma from Naniarchar Upazila on Apr 5. He died at Chittagong Medical College Hospital while in custody on Apr 19.
The demonstrators claimed that he died from torture by the army, but the Army refuted the allegation.
PCP Rangamati unit President Kunentu Chakma, Hill Women's Federation's Central General Secretary Monty Chakma spoke at the programme.