Bangladesh has seen the fourth murder of a blogger with secularist views in 2015, adding to the already existing concerns about freedom of speech in the country.

Niloy Chatterjee, who used the pen-name Niloy Neel, was hacked to death last Friday after men broke into his flat in the capital Dhaka 's Goran neighbourhood.

The blogger's complaint to the police about threats that he received had been reportedly disregarded by the police.

Ansar-Al-Islam, a local chapter of al-Qaeda, claimed responsibility for the murder.

Two days later, the inspector general of the police forces in the country, warned bloggers against writing blogs that may hurt religious sentiments. 

"No one should cross the limit," AKM Shahidul Haque said.

Secularism is a fundamental principle in the constitution of the Muslim-majority country.

Communal tensions have been high in the country in recent years, amid increasing violence against minorities, according to local human rights groups.

Al Jazeera discussed the 2015 blogger murders with Zafar Sobhan, the Dhaka Tribune's editor-in-chief, who also writes for various global English-medium publications.     

Al Jazeera: Who are these bloggers? What do they have in common and what do they usually write about?

Zafar Sobhan: The bloggers are a loose collection of individuals who are associated with a website, Mukto Mona , which is a platform for free-thinkers.

They have raised questions about religious faith - all faiths - and the role of religion in society, and have been critical of extremism and militancy.