Niloy Neel was killed by assailants inside his fifth- floor flat at North Gorhan in the capital Dhaka.
"The assassins used machetes... It appears they hit him repeatedly until he was dead," Mostafizur Rahman, officer in charge of the police station in the neighbourhood, told PTI.
He said Neel, an official of a non-government organisation, used to live in the apartment building along with his family members and was known for his secular write ups in blogs.
Neel was an activist of a platform -- the Ganajagaran Mancha which waged a massive campaign for the capital punishment for war criminals who carried out atrocities siding with the Pakistani troops in 1971.
More From This Section
"Niloy was also a regular blogger...He was a target of the Islamists," Imran H Sarker, the Ganajagaran Mancha spokesperson, said, adding the attackers had entered the building posing as potential tenants.
Media reports said Criminal Investigation Department (CID) joined the police in collecting evidence related to the incident.
Neel's murder is the fourth such brutal murder in the country. Machete-wielding masked men in May hacked to death 33-year-old Ananta Bijoy Das, a secular blogger, in Sylhet city.
A month after Roy's killing, another blogger Washiqur Rahman was murdered in similar fashion in Dhaka but people in the neighbourhood nabbed two suspected killers from the scene and handed them over to police.
All three killed were involved with the Ganajagaran Mancha.
In May, terror group al-Qaeda in the Indian Subcontinent (AQIS) had claimed responsibility for the killing of secular bloggers in Bangladesh whom it described as 'blasphemers'.
Radical group Ansar Bangla Team had also claimed responsibility for the deaths.
Police earlier said they suspected banned Ansarullah Bangla Team (ABT) having links to al-Qaeda was involved in the murders of the secular bloggers in the recent months.
Several suspected operatives of the ABT were arrested after the it claimed responsibility for the murder of three bloggers.