Armed men entered a publishing house in Bangladesh's capital city of Dhaka and stabbed and shot the publisher and two writers while another publisher was killed by militants on Saturday.
Both publishers had published the works of slain author Avijit Roy, who was hacked to death by Islamists earlier this year for his critical view of religion.
Ahmedur Rashid Tutul , publisher of the publishing house Shudhdhoswar Prokashani, was said to be a close friend of Roy and had published one of his books, Dhaka Tribune reported.
Another one of Avijit Roy's publisher Faisal Arefin Dipanwas was also attacked on Saturday, Bangladeshi media reported.
Faisal reportedly succumbed to his injuries. His publishing house Jagriti Prakashani had published Avijit Roy's book Biswasher Virus( The Virus of Faith).
Shuddhashar Prokashani had published Roy's book Shunya Theke Mahabishwa.
At least six assailants with guns and weapons entered the Shuddhashar Prokashani office in Dhaka and hacked the publisher and at least two writers.
The three are said to be in critical condition following the attack.
Avijit Roy was hacked to death in the middle of a busy road on 26 February by militants of the Ansarullah Bangla Team.
The Islamist outfit also attacked and killed three other bloggers in recent months, bringing global focus on the rising extremism in Bangladesh.