- Al-Qaeda affiliate claims its members undertook the attacks
- Blogger is the fifth to be killed in Bangladesh this year
- Police said they have yet to identify any suspects
Publisher and secular blogger Faisal Arefin Dipan was killed in Shahbagh area while three others, also publishers and bloggers, were hacked and shot in Lalmatia area.
Muntasirul Islam, a deputy commissioner and spokesman of Dhaka Metropolitan Police told journalists that unidentified assailants were involved in the attacks.
Al-Qaeda in the Indian Subcontinent, or AQIS, claimed responsibility for the assaults, saying Dipan and the others made derogatory remarks about the Muslim faith.
The attackers struck inside publishing houses where the men worked, the spokesman said.
"It's been seemed pre-planned and (an) act of terror," Islam said, adding that police were yet to make any arrests.
Both Dipon and Ahmedur Rashid Tutul, who was being treated at Dhaka Medical College Hospital, published books of slain Bangladesh-born American blogger and writer Avijit Roy.
Roy was murdered in a similar attack in an annual book fair on Dhaka University campus in February.
A month later, Washiqur Rahman, 27, was savaged by two men with knives and meat cleavers just outside his house as he headed to work at a travel agency in the capital.
Anant Bijoy Das
, 32, was set upon with cleavers and machetes in May as he left his home on his way to work at a bank in northeastern Bangladesh. And in September, Niloy Neel was hacked to death in his Dhaka apartment.
Ranadipam Basu and Tareq Rahim, who were wounded in Saturday's attacks, were hospitalized at Dhaka Medical College.