Dr Avijit Roy was attacked on Thursday night by cleaver-wielding extremists by


This is the moment a prominent Bangladeshi-American blogger was hacked to death in the street by militant Muslims after denouncing religious extremism.

Dr Avijit Roy, 42, from Atlanta, Georgia, was jumped by the gang of machete-wielding assailants last night in Dhaka, the capital of Bangladesh - leaving his injured wife standing over his bleeding body. He is well-known in Bangladesh for for his outspoken atheism.

An obscure militant group, Ansar Bangla 7, claimed responsibility for the attack, which it said was in retaliation for his 'crime against Islam'.

The extremists also said he was singled out because he is a U.S. citizen - and characterized the vicious killing as 'revenge' for attacks on ISIS in Syria.

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Brutal: This image, circulated by extremists on social media, shows Dr Avijit Roy dead on the floor in Dhaka, Bangladesh (right) on Thursday night. Left, his wounded wife, Rafida Ahmed, stands over his body

Outspoken: Blogger and author Dr Roy, 42, was described as a 'free thinker' with a 'strong voice against Islamic fanatics,' by a friend

Murder: The body of Avijit Roy was found in a pool of blood after being attacked by a clever wielding gang in Dhaka, Bangladesh on Thursday night

Police said at least two men, who are believed to have links to Dhaka University, attacked Roy around 8.45pm and landed three strong, deliberate blows to the right side of his head.

They turned on his wife, Rafida Ahmed, when she tried to save him, then fled into the crowd, dumping their weapons as they ran. Police have expressed shock that extremists struck at a university book fair, which was heavily guarded.

Witnesses have even said officers and bystanders were there during the murder - but did nothing. Several onlookers told Al-Jazeera nobody intervened in the brazen attack, while even police chiefs had said they were baffled that a man could be murdered so close to the heavily-guarded area.

The United States today said the murder was 'horrific in its brutality and cowardice' and represents an attack on the 'principles' of Bangladesh.

Roy's body was found in a pool of blood on Thursday night after the brutal attack. Ahmed, 45, is also a blogger. She is reportedly now in hospital with a deep cut to her head.

Roy, who is a naturalized U.S. citizen and also a bio-engineer, had been receiving death threats online for years.

One Muslim fanatic, Farabi Shafiur Rahman, had reportedly posted threats on Facebook last year that Roy would be killed as soon as he returned to the country.

Roy and his wife were visiting the city of Dhaka for a book fair when they were set upon opposite the Dhaka University Central Mosque. Police have said the attackers likely have links to the university.

Jubilant extremists writing on social media were quick to praise the attackers. The account for Ansar Bangla 7 made a post which linked the killing to Roy's nationality - and American airstrikes on ISIS.

Survivor: Rafida Ahmed is pictured above being stretchered to hospital after the attack on Thursday night. Police say she was attacked after trying to defend her husband

Home: Dr Roy and his wife, Rafida Ahmed, lived in Atlanta, Georgia, and were visiting Bangladesh when they were attacked

It said: 'The target was an American citizen.. 2 in 1. #America recently martyred 2 of our brothers in #Khurasan & #Shaam. #Revenge+#Punishment.'

Khurasan refers to Afghanistan. Shaam is a term for Syria, where American airstrikes have been a major part of the fight against ISIS.

They also said he had been their 'top target', and tried to justify the killing by saying he 'crossed his limit' after being 'warned many times'.

According to an autopsy report obtained by local site BDNews24, Roy was killed by three deep gashes, which cut through his skull to the brain.

Doctors examining Roy's body said the attack had the hallmarks of professional killers, who acted with 'planning, skill and brutality'.

BDNews24 reported that she had lost a finger in the attack and had a deep gash to her head.

Police are yet to arrest anybody over the killing - and said on Friday they still have no leads - though they think the killing is linked to the university.

Claiming responsibility: Militant group Ansar Bangla 7 said they were behind the murder - and linked it to U.S. action against ISIS

Target: Messages posted by the militant group strongly linked the attack to his American citizenship

Family: The couple have a daughter who is at college in the U.S. - the picture above is believed to show Roy with his wife and the young woman

Hunt: Police are investigating the killing in Dhaka, Bangladesh but have not yet made any arrests following the bloody attack

Threats: Farabi Shafiur Rahman, pictured, reportedly threatened Roy with death should he come back to Bangladesh

Bangladesh News 24 quoted a police spokesman saying the murder was 'university-centric'.

He said: 'Those who had come to kill [Roy] with machetes were not outsiders. This is university-centric'.

Roy was of a Hindu background - a religious minority in Bangladesh which which has been historically persecuted. He is also the son of a prominent secularist and human rights activist, Ajay Roy.

He was a prominent voice against religious intolerance, who had been sent death threats over his writings.

Chief Sirajul Islam said said: 'Several attackers took part in the attack and at least two assailants hit them directly,' Islam said, adding that two blood-stained cleavers were found after the attack. '

Shilby Noman, Dhaka's assistant police commissioner, said: 'Nothing of note has been revealed so far.

'But we hope that we'll be able to arrest them and bring them to book so that this kind of crime does not take place again.'

Grief: Dr Roy's father, retired professor and activist Ajay Roy, called for his killers to be punished on Friday

Torches raised: This crowd of women marched through Dhaka Friday night in Bangladesh in protest

Tribute: This candle-lit memorial was set up near the site of the murder in honor of Roy

Roy was often threatened over his writings, which appeared online, in newspapers and in several published books.

Police sources in Dhaka say that, despite the violent threats, he had never asked them for protection.

According to the Dhaka Tribune, the religious extremist Farabi Shafiur Rahman was one of those leaving threats.

He is said to have written: 'Avijit Roy lives in America. So it's not possible to kill him now. He will be killed as soon as he returns home.'

In a later post, he is said to have continued: 'It’s now time to openly kill those atheists who will make obscene comments against Allah and His Messenger, giving them slow, painful death... In Bangladesh, either we Muslims will survive or the atheists will.'

The Guardian reported that he was arrested for the comments - but it is unclear whether or how soon he was released.

Roy was the founder of a popular Bengali-language blog - Mukto-mona, or Free Mind - in which articles on scientific reasoning and religious extremism featured prominently.

On its pages, Roy had recently published a defense of atheism, writing in January that it was 'a rational concept to oppose any unscientific and irrational belief.'

Next day: A worker is pictured above cleaning the blood from the street where Roy was hacked down by his attackers

Together: The husband and wife were jumped by the gang after leaving an event. Rafida Ahmed was beaten, bruised, and lost a finger - but survived

The website was shut down in the wake of the attack and now displays a message in Bengali, which reads: 'We are in mourning, but not vanquished'.

Roy has also written several books - two of which had been launched earlier in the book fair he was visiting.

Roy's father, retired professor and secular activist Ajay Roy, called for harsh punishment of his son's killers, and said their actions were a sign of Bangladesh's declined.

He told reporters: 'The Bangladesh that was earned by the blood-sacrifice of the martyrs has now turned into a den of militants.

'I demand that the government immediately stops militant activities, vbbrings them to book and ensures exemplary punishment.'

Hundreds of students and activists gathered in Dhaka today to mourn Mr Roy's death and protest against the intimidation and murder of secular writers.

Islam is Bangladesh's state religion but the country is governed by secular laws based on British common law, and Prime Minister Sheikh Hasina has repeatedly said she will not give in to religious extremism.

Anujit Roy, his younger brother, said Roy returned to the country earlier this month from the U.S., and headed back in March.

Baki Billah, a friend of Roy and a blogger, told Independent TV that Roy had been threatened earlier by people upset at his writing.

'He was a free thinker. He was a Hindu but he was not only a strong voice against Islamic fanatics but also equally against other religious fanatics,' Billah said.

'We are saddened. We don't know what the government will do to find the killers. We want justice,' he said

Memorial: Tributes: People were today gathering at the spot where the blogger was ambushed and hacked to death

International condemnation was also mounting over the murder.

State Department spokesman Jen Psaki addressed the killing in a briefing today. She said: 'The United States condemns in the strongest terms the brutal murder of Avijit Roy, which was horrific in its brutality and cowardice.

'He was a journalist a humanist a husband and a friend and we extend our condolence. He was taken from us in a shocking act of violence.

'This was not just an attack against a person, but a cowardly assault on the universal principles enshrined in Bangladesh's constitution and the country's proud tradition of free, intellectual and religious discourse'.

She said the U.S. embassy would help Bangladeshi authorities if asked - but refused to comment on possible reasons for the killing.

Representatives of the European Union in Dhaka said: 'The Delegation of the European Union to Bangladesh condemns the brutal assault and killing of blogger Avijit Roy and wounding of his wife last night in Dhaka.

'The EU reiterates its strong attachment to freedom of expression which constitutes an essential element of a democratic society and calls for a prompt investigation to bring perpetrators to justice.'

Meanwhile Robert Gibson, the British High Commissioner to Bangladesh, said on Twitter he was: 'Shocked by the savage murder of #AvijitRoy as I am by all the #violence that has taken place in #Bangladesh in recent months'.

Similar attacks have taken place before in Bangladesh, a Muslim-majority nation of 160 million people ruled by secular laws. Investigators have said religious fanatics were behind those attacks.

HACKED DOWN FOR BLOGGING: BANGLADESH'S HISTORY OF VIOLENCE Dr Avijit Roy is the latest in a line of figures standing for free speech who have been killed for expressing their views. In 2013, another atheist blogger, Ahmed Rajib Haider, who also spoke out against religious extremism, was murdered near his Dhaka home. Those attackers also used machetes, and left Haider's body so badly mutilated it could not be identified. In 2004, Humayun Azad, a prominent writer and a teacher at Dhaka University, was attacked just yards from the spot where Roy was murdered. Azad, who was also subject to religious threats, was seriously injured but ultimately survived the assassination attempt. Writer Taslima Nasreen also received death threats from Islam extremists in the mid 1990s. 'Avijit Roy has been killed the way other free thinker writers were killed in Bangladesh. No freethinker is safe in Bangladesh,' she said on her blog according to the BBC. Advertisement

Outrage: Bangladeshi students and social activist have taken to the streets to protest against the killing