Bangladesh vowed on Friday to catch the killers of a law student murdered after criticising Islamists on social media as hundreds of secular activists held a protest demanding justice.

Nazimuddin Samad, 26, was killed late on Wednesday near his university in the capital Dhaka by unknown assailants carrying machetes.

It was the latest in a series of killings of secular bloggers and campaigners in Bangladesh and has sparked international outrage, as well as demands for the government to protect freedom of speech in the Muslim-majority country.

Police on Friday filed a murder case and said that they were treating his death as a "targeted killing".

Abu Hena Muneem, a senior home ministry official, dismissed claims that the government was failing to protect secularists and said authorities were doing all they could to track down Samad's killers.

"The accusations are not correct. Our law enforcement agencies are working very hard to find the culprits and they will soon be arrested," Muneem told AFP news agency.


READ MORE: Bangladesh activist Nazimuddin Samad hacked to death


Activists, however, expressed concerns about the government's readiness to protect them as they held a protest march in the capital.

About 400 people chanted slogans including "stop the culture of impunity, save secular Bangladesh".

"It is very worrying," said Imran Sarker, a spokesman for Bangladesh's biggest secular activists' group, Gonojagoron Mancha.

"We wonder whether the government actually has the goodwill to put an end to this."

Samad's murder was the sixth such killing in 15 months.

His childhood friend and fellow activist Gulam Rabbi Chowdhury said he had gone into hiding before the attack and deactivated his Facebook page for a number of months.

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Source: AFP