By Ruma Paul
DHAKA (Reuters) - Bangladeshis gathered on Sunday to pay tribute to an American blogger and critic of religious extremism who was hacked to death in Dhaka, in the latest of a series of attacks on writers in the Muslim-majority nation.
Avijit Roy, a U.S. citizen of Bangladeshi origin, was killed by machete-wielding assailants on Thursday while returning from a book fair.
His wife and fellow blogger Rafida Ahmed suffered head injuries and lost a finger. She remains in hospital in a serious condition.
The attack came amid a crackdown on hardline Islamist groups, which have increased activities in recent years in the South Asian nation of 160 million people.
Mourners gathered with flowers on Sunday to pay their respects to Avijit, who was in his native city on a visit from the United States.
Students, professors and writers were among those laying flowers on Avijit's coffin, placed in the grounds of Dhaka University.
"Free thinking in Bangladesh is becoming a great danger, all the free thinkers are at great risk," writer Shahriar Kabir said.
"We want to know why the government failed to ensure the safety of him, despite knowing that he had been facing threats from the Islamist radicals."
No arrests have been made. A demonstration was also held at the spot where Avijit was killed. Protesters chanted slogans demanding the "immediate arrest and quick trial of the perpetrator".
Avijit's family said Islamist radicals had been threatening him because he maintained a blog, "Mukto-mona," or "Freemind," that highlighted humanist and rationalist ideas and condemned religious extremism.
"An Islamist militant group is behind the murder. The fundamentalists were threatening to kill him," Avijit's father Ajoy Roy said at the gathering.
U.S. State Department spokeswoman Jen Psaki called it "a shocking act of violence" that was "horrific in its brutality and cowardice".
In 2013, religious extremists targeted several secular bloggers who had demanded capital punishment for Islamist leaders convicted of war crimes during Bangladesh's war for independence.
Blogger Ahmed Rajib Haider was killed that year in a similar attack near his home in Dhaka after he led one such protest demanding capital punishment.
In 2004, Humayun Azad, a secular writer and professor at Dhaka University, was also attacked by militants while returning home from a Dhaka book fair. He later died in Germany while undergoing treatment.
Media group Reporters Without Borders rated Bangladesh 146th among 180 countries in a ranking of press freedom last year.