Months after a secular blogger was hacked to death in Bangladesh's capital, a publisher who published the writer's books has been killed. The attack came hours after men stabbed another of the blogger's publishers, along with two other writers.

Both of the publishers had published the writings of Aijit Roy, a Bangladeshi-American who was hacked to death in February on a sidewalk in Dhaka, the capital of Bangladesh.

In Saturday's attacks, publishing house owner Faisal Arefin Dipan was stabbed to death in an office that was situated above a supermarket, according to the Dhaka Tribune.

Dipan's publishing house, Jagriti Prakashani, published one of Roy's final works, titled Biswasher Virus "The Virus of Faith."

News of the attack on Dipan closely followed a similar one on another publisher, Ahmedur Rashid Tutul, who was set upon in his office along with two other people, both of them bloggers. In each attack, The Daily Star reports, "the perpetrators locked the victims inside their offices before leaving the scene."

Blogger Ranadipam Basu, one of the bloggers who was stabbed along with Tutul, evidently helped alert people to the attack — and his need for help — by posting a short message to Facebook minutes after the assault, reading, "They hacked us – Tutul, Tareq and me," according to The Daily Star.

Those three are now in the hospital, the newspaper reports.

The publisher Tutul was a close friend of Roy's, reports BDNews24.

In his writings, Roy denounced fundamentalist ideas and promoted rational thinking; he also founded the website Free Mind, to rally "free thinkers, atheists and humanists of mainly Bengali descent," as NPR reported in February.

The Center for Inquiry, a U.S.-based nonprofit that advocates for secular humanism and that also worked with Roy, has released a statement expressing "outrage at the killing, and at the Bangladeshi government's unwillingness to confront the crisis and protect its people."

NPR's Julie McCarthy, reporting from the region, says that al-Qaida in the Indian Subcontinent claimed responsibility, according to the Intelligence Group SITE that monitors jihadist activity on-line. In an earlier statement in May, the group also claimed to have killed Roy.

Amnesty International urged the government to protect other independent thinkers and called "further chilling evidence of the horrific pattern of violence against people exercising their freedom of expression in the country," Julie reports.

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