In this task, you are given an article. Your task is to summarize the article in a sentence.

[EX Q]: Avijit Roy, an atheist who advocated secularism, was attacked as he walked back from a book fair with his wife, who was also hurt in the attack.
No-one has been arrested but police say they are investigating a local Islamist group that praised the killing.
Hundreds of people gathered in Dhaka to mourn the blogger's death.
Mr Roy's family say he received threats after publishing articles promoting secular views, science and social issues on his Bengali-language blog, Mukto-mona (Free Mind).
He defended atheism in a recent Facebook post, calling it a "rational concept to oppose any unscientific and irrational belief".
His Mukto-mona website on Friday bore the message in Bengali "we are grieving but we shall overcome" against a black background.
US State Department spokeswoman Jen Psaki described it as an assault on Bangladesh's proud tradition of free intellectual and religious speech.
A group of men ambushed the couple, who live in the US and were visiting Dhaka only to attend the book festival, as they walked toward a roadside tea stall.
At least two of the attackers hit the couple with meat cleavers in the attack on Thursday evening, police chief Sirajul Islam told AP news agency.
Dropping their weapons, the attackers ran away, disappearing into the crowds.
Police told the BBC they were investigating a local hard-line religious group that had praised the killing in an online message.
Ajay Roy, father of the dead man, urged the authorities to find the killers and "ensure exemplary punishment".
"This Bangladesh which was built  by the blood-sacrifice of the martyrs has now turned into a den of militants," he said.
Students, teachers and bloggers gathered at Dhaka University on Friday to protest against the killing.
In a forthcoming article to be published in the Free Inquiry magazine of April-May 2015, Mr Roy likens religious extremism to a "highly contagious virus".
He says he received threats from Islamist hardliners in Bangladesh last year when his book, The Virus of Faith, was released at a book fair.
"The death threats started flowing to my e-mail inbox on a regular basis," he writes.
"I suddenly found myself a target of militant Islamists and terrorists. A well-known extremist... openly issued death threats to me through his numerous Facebook entries.
"In one widely circulated status, he writes, 'Avijit Roy lives in America and so, it is not possible to kill him right now. But he will be murdered when he comes back.'"
The killing in early 2013 of another secular blogger, Ahmed Rajib Haider, which was blamed on religious hardliners, sparked protests from free-speech supporters and counter-protests from Islamists.
The police say the attack on Mr Roy was similar to the 2013 murder.
Avijit Roy
Death threats against atheist writers and bloggers are nothing new in Bangladesh.
Prominent writer Taslima Nasreen had to leave Bangladesh after she received death threats from hard-line Islamists in the mid-1990s.
She wrote on her blog: "Avijit Roy has been killed the way other free thinker writers were killed in Bangladesh. No free thinker is safe in Bangladesh.
"Islamic terrorists can do whatever they like. They can kill people with no qualms whatsoever."
[EX A]: Attackers in the Bangladeshi capital Dhaka have hacked to death a US-Bangladeshi blogger whose writings on religion angered Islamist hardliners.

[EX Q]: 13 December 2016 Last updated at 08:48 GMT
Laugh-til-you're-crying? Gritted teeth? Maybe heart eyes?
Last night the BBC Music Awards took place in London.
Adele was the big winner of the night taking song of the year for Hello, and album of the year, for 25.
Ricky caught up with some of the biggest names in the music industry to find out which Emoji they'd use to describe their year.
[EX A]: How would you describe your year if you had to choose an emoji?

[EX Q]: Roger Caffrey is charged with three counts of rape and 14 indecent assaults in Nottinghamshire dating between 1978 and 1995.
Sixteen of the 17 charges involve girls under the age of 16 - some thought to be as young as nine.
Mr Caffrey, who taught at 10 schools in the county, denies all the charges.
Updates on this story and more from Nottinghamshire
Nottingham Crown Court heard Mr Caffrey's teaching career spanned more than three decades from 1966.
He told the court he taught all subjects, and later became a specialist in helping schools through Ofsted inspections.
The 70-year-old, now of Sandesquoy, Tankerness, Orkney, is accused of raping two girls at his then home and touching pupils while they read aloud in class or touching them in a store cupboard in the classroom.
Mr Caffrey admitted that he would put his arms around pupils' waists, or, on some occasions, pat them on the "side of the buttock" to praise them after they read in front of class.
"It just seemed the natural thing to do," he said. "It was encouragement back in those days.
"Obviously it's different today. There was nothing sexual [about it]."
Mr Caffrey said one of his former pupils - who has accused him of raping her - was the kind of person he would have liked his daughter to have been.
"She was very athletic and she'd got a lot of guts, grit and determination," he said.
"I had no sexual feelings [towards her]. I had no sexual feelings towards any of my pupils."
The jury heard Mr Caffrey, who has been married three times, left his first wife while she was pregnant to live with a member of school staff.
He admitted having another "brief affair" with a staff member at a primary school where he worked until 1984.
"I was a womaniser," he said. "I'll plead guilty to that."
The trial continues.
[EX A]:
A former teacher accused of rape and sex abuse told a court he did pat pupils "on the side of the buttock", but denied any sexual intention.

