Statements attributed to a regional division of Al Qaeda late on Saturday claimed responsibility for attacks on two publishers in Bangladesh who put out works critical of fundamentalist Islam, according to the SITE Intelligence Group, which monitors radical Islamic propaganda.
The two men were stabbed, one fatally, eight months after a similar attack on Avijit Roy, a Bangladeshi-American known for his critical writings on religious extremism, the police said. Both publishing houses had issued Mr. Roy’s works.
One of the publishers, Faisal Arefin Dipan, died of his wounds immediately, the police said. The other, Ahmed Rahim Tutul, was in critical condition late Saturday.
The claim of responsibility by the division, Al Qaeda in the Indian Subcontinent, was made in statements posted on Twitter on Saturday. One of them said the two men were “worse than the writers of such books, as they helped propagate these books and paid the blasphemers handsome amounts of money for writing them.” A second statement, titled “Who’s Next,” describes categories of people as “our next targets.” The list includes writers, poets, intellectuals, newspaper or magazine editors, reporters and actors.
The statements will feed into a debate over whether transnational terrorism groups have an organizational presence in Bangladesh, and they follow three similar statements that said the Islamic State had carried out attacks on foreigners and Shiite Muslims.
Bangladesh’s prime minister, Sheikh Hasina, has been adamant that the rise in targeted violence is emanating from political opposition figures in Bangladesh, and the police have named or arrested suspects with links to two main opposition groups, the Bangladesh Nationalist Party and Jamaat-e-Islami, an allied Islamist party.
Officials have dismissed social media claims, such as the ones made on Saturday, as inauthentic.
Mr. Tutul, the wounded publisher, had received death threats on his cellphone over books that he had published, Mizanur Rahman, the director of publicity for the Academic and Creative Publishers Association, said in a telephone interview.
The attacks build on a rise in extremist violence in Bangladesh this year. Mr. Roy’s killing, in February, was followed by three more nearly identical assassinations of bloggers and intellectuals who have criticized fundamentalist Islam. In May, the leader of Al Qaeda in the Indian Subcontinent released a video claiming responsibility for the murder of Mr. Roy and one other writer, whom he described as “blasphemers.” Ajoy Roy, the father of Avijit, the murdered blogger, said he believed that Mr. Tutul was targeted because he had published his son’s book.
As “hit lists” of secular writers circulate on the Internet, many writers and journalists have become hesitant to publish work that could attract the attention of Islamists, and a growing list of activists, fearing for their lives, have applied for asylum in Western countries.
Around 3 p.m. on Saturday, a group of men entered the Shuddhashar publishing house, saying they wanted to buy books, said Biplob Kumar Sarker, the deputy police commissioner in Dhaka. They then held two men at gunpoint while other assailants attacked the publisher, Mr. Tutul, and two men who were in his office, Mr. Sarker said. The assailants locked the doors from the outside when they left the premises, and the police said that after breaking the locks, they had found all three men on the floor with severe stab wounds.
One of the other victims was Sudip Kumar Barman, who blogs under the name Ranadipam Basu and has published commentaries on the website curated by Avijit Roy before his death.
About the same time, three men entered the offices of Jagriti Publications, where they found Mr. Dipan, 43, alone and stabbed him, leaving him with fatal neck wounds, said a spokesman at the Shahbag police station. He was pronounced dead at Dhaka Medical College Hospital.
Mr. Dipan’s business had published “The Virus of Faith,” the book that made Mr. Roy a target for militant groups.
Mr. Dipan’s father, Abul Quashem Fazlul Huq, said in an interview that after hearing about the attack on the first publisher, he became worried about his son and tried to reach him by phone. He went to his son’s business and, once the authorities had broken the lock, walked into his office, and saw he was not in his chair.
“I saw that his neck was cut,” he said. “The whole floor was covered with thick blood. I could not stand there anymore. I left the place.”
For decades, Bangladesh has struggled to contain a network of domestic militant cells, some of them linked to political opposition groups. They have regrouped this year, carrying out a series of killings, often in crowded spaces in broad daylight.
Over the last month, the attacks and threats have proliferated. A month ago, Western intelligence services received information suggesting that the Islamic State terrorist group had plans to ramp up its activities in Bangladesh. Shortly thereafter, two foreigners were shot.
On Monday, the Ansarullah Bangla Team, a homegrown terrorist group, sent a letter to a Bangladeshi cable news station threatening attacks on news outlets if they continued to allow unveiled women to report the news. On Oct. 24, bombers targeted a huge procession of Shiite Muslims in Dhaka, killing a teenage boy. It was the first time in memory that the country’s tiny Shiite minority had come under attack.