Placard-waving students blocked traffic on a key street throughout Thursday to demand the arrest of the murderers within 48 hours.
Several organisations joined the demonstration.
They rallied, marched through the streets and organised human-chain programmes.
After recovering the body, police, based on the findings at the crime scene, had said that the girl was first raped and then murdered.
“Police are trying to solve the murder case. Police will find the murderers and the people behind them, however powerful they are,” Additional Superintendent of Police Imtiaz Ahmed said.
“We will arrest the murderers soon,” he said.
Victoria College Theatre General Secretary Farhana Ahmed wondered how such an incident could occur in a secured place like a cantonment.
Tonu was an activist of the organisation.
Raging posts over the murder also flooded the social media.