Bangladeshi-American atheist blogger Avijit Roy was hacked to death by machete-wielding thugs in Dhaka on Thursday evening. His wife, blogger Rafida Ahmed, was also seriously wounded. Roy had reportedly received threats from Islamists before his death, including an online statement two months ago that called for his murder. Bangladesh has been struggling for years over the role of Islam in its politics, and atheist bloggers have been targeted in the past. In 2013, another blogger was killed in a similar attack, and the government arrested several writers and blocked websites in a crackdown on religious dissent.

Roy was attacked by machete-wielding thugs

In an attack that some are comparing to the Charlie Hebdo killings, Avijit Roy, a prominent Bangladeshi-American atheist blogger, was hacked to death on Thursday evening in Dhaka by two machete-wielding thugs. His wife Rafida Ahmed, who was with him at the time, was also seriously wounded in the attack.

According to AFP, Roy and Ahmed were returning home from a book fair when the attackers forced the bicycle rickshaw they were riding in to stop. They dragged Roy and Ahmed from the vehicle and then attacked them with machetes.

Roy is reported to have died on the way to the hospital.

Roy's murder has sparked outrage in Bangladesh not just over the crime, but over what many see as a larger problem of Islamist violence. His death prompted a large demonstration in Dhaka. Hundreds of protesters gathered to demand justice for Roy and denounce his killers.

The protesters carried signs and chanted "we want justice." The head of the Bangladeshi bloggers' association, Imran Sarker, said that Roy's murder had "once again proved that there is a culture of impunity in the country" and that the government must arrest the killers within 24 hours or "face non-stop protests."

Roy's father has reportedly blamed Jamaat-e-Islami, a popular Islamist party, for "backing" the militants who murdered his son. In response, the party's acting secretary general issued an angry press release denying any involvement in Roy's murder, and calling for the authorities to conduct a "credible and fair" investigation to find the "real murderers."

Islamists had reportedly threatened Roy before over his outspoken atheism

Roy described himself on his Facebook page as an "engineer by profession and a writer by passion." He had a "profound interest," he said, in "freethinking, skepticism, philosophy, scientific thoughts and human rights of people." He had won acclaim within the community of Bangladeshi atheists and bloggers for his writing.

Hardline Islamist groups have demanded laws prohibiting criticism of Islam and have called for the execution of atheist bloggers like Roy. Roy's father told the AFP that Roy had received threats on email and social media from Islamists who objected to his work.

Roy's work was well known in Bangladesh. He ran his own website, Mukto Mona, until several years ago, and was the author of ten books. According to The Independent, his most recent books, Biswasher Virus ("Virus of Faith") and Obisshahser Dorshon ("The Philosophy of Disbelief"), were controversial but critically well-received. Although Roy had suspended his work on Mukto Mona several years ago, today the site's content has been replaced with a single message in Bengali: "We mourn, but we are not defeated."

In December 2014, Bangladesh News 24 reports, a man named Shafiur Rahman Farabi had posted a message on a web forum lamenting that it would not be possible to kill Roy while he was in the United States, but that he would be murdered when he returned to Bangladesh. "Abhijit Roy lives in America and so, it is not possible to kill him right now. He will be murdered when he comes back."

The Guardian reports that Farabi was arrested for making those threats, but that it was not clear whether he was free at the time of Roy's murder.

Protests over Roy's death show the depth of controversy over atheism and religion in Bangladesh

To understand how Roy's life and murder fit into the larger issue of religion in public life in Bangladesh, it helps to look at another atheist blogger who was murdered in a machete attack, in 2013: Ahmed Rajib Haider.

Four students who were members of a little-known Islamist extremist organization confessed to his killing.

Haider had been a prominent voice in the 2013 Shahbag protests, which called for a death sentence for Islamist politician Abdul Quader Mollah over his role in crimes against humanity during Bangladesh's 1971 war of independence. The protests also demanded that Mollah's party, the same Jamaat-e-Islami that Roy's father blamed for his son's death, be barred from Bangladeshi politics.

Haider's death triggered protests by thousands of secular activists. However, Islamist groups also increased their campaigns against other atheist bloggers, calling for them to be executed for blasphemy.

The Islamist campaign was partially successful: the government arrested several prominent atheist bloggers and blocked a number of atheist websites. Human Rights Watch issued a statement at the time of the arrests, calling the detained bloggers "political prisoners" who had been jailed for peacefully expressing their views.

This is the political climate that Roy, and others like him, have operated in for years. It is one in which secular activists have never stopped pushing for the right to express their ideas publicly; but also one in which powerful Islamist groups believe that those secular voices should be silenced — if necessary, by death.