NEW DELHI — Two businessmen who had published the works of Avijit Roy, a Bangladeshi-American known for his critical writings on religious extremism, were stabbed on Saturday by groups of men in the Bangladeshi capital, Dhaka, the police said. The attack came eight months after Mr. Roy was himself stabbed to death with machetes.

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.

Mr. Tutul 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 an already unsettling 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’s branch 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.