A Bangladeshi student who expressed pro-atheist views online was hacked to death Wednesday night as he walked with a friend in the capital, Dhaka.

Nazimuddin Samad, who had only recently moved to Dhaka to study law, is the latest in a growing list of secular bloggers killed by religious extremists in the officially secular country.

So concerning has the trend become that last year over 150 writers, including Salman Rushdie and Margaret Atwood, published an open letter to Prime Minister Sheikh Hasina and her government, urging her "to do all in their power to ensure that the tragic events of the last three months are not repeated, and to bring the perpetrators to justice."

"We are gravely concerned by this escalating pattern of violence against writers and journalists who are peacefully expressing their views," the letter said.

In the latest incident, three machete-wielding men on a motorcycle approached Mr. Samad and his friend, attacked the law student with their blades and then shot him once he fell to the ground.

Police suspect Samad was targeted because of his outspoken atheism in this majority-Muslim country, as well as his support of a 2013 movement to demand justice for war crimes committed during Bangladesh’s war of independence with Pakistan in 1971.

As Samad’s assailants stole his life, they were chanting “Allahu Akbar” (God is Greatest), reported the Dhaka Tribune.

"We urge the Bangladeshi police and other authorities to do everything in their power to investigate and prosecute this vicious attack on free speech and thought, and halt this terrible pattern of murders," said Karin Deutsch Karlekar of PEN America, an association of 4,400 US writers.

"We also reiterate our demand for the United States and other countries that are able to provide refuge to shelter those writers who are still at grave risk before more lives are lost."

Four prominent bloggers were all murdered with machetes last year, one in his own home after six men tricked their way inside and confined his wife to another room.

All four had appeared on a list of 84 “atheist bloggers,” compiled by Islamic groups and given wide circulation in 2013, according to the BBC.

Religious minorities have also suffered such attacks in Bangladesh, with Shia, Sufi, and Ahmadi Muslims, Christians, and Hindus all being targeted.

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"The government of Bangladesh must do much more to protect its own people from marauding Islamist killers," said Michael De Dora of the Center for Inquiry.

"The Bangladesh government must publicly and forcefully defend the universal human rights to freedom of religion, belief, and expression, fully investigate and prosecute these crimes, and show that attacks on individuals based on their beliefs or expressions will not be tolerated."