A man holds a portrait of Bangladeshi professor Rezaul Karim Siddique, who was hacked to death by unidentified attackers, in Rajshahi on April 23, 2016. (AFP Photo)

Highlights Rezaul Karim Siddique, 58, hacked to death with machetes

Killing claimed by ISIS jihadists, in line with that of several bloggers

May have been targetted for encourgaing music, literature: Acquaintances

A university professor was hacked to death by attackers armed with machetes in northwestern Bangladesh on Saturday, a killing claimed by ISIS jihadists and echoing the murders of several secular bloggers.The assailants almost beheaded English professor Rezaul Karim Siddique, 58, when they attacked him from behind as he walked to the bus station from his home in the city of Rajshahi, police said."By examining the nature of the attack, we suspect that it was carried out by extremist groups," Rajshahi Metropolitan Police commissioner Mohammad Shamsuddin told AFP.The ISIS group claimed the murder of Siddique, the fourth professor from Rajshahi University to be killed by Islamists.Militants have also targeted secular bloggers and students in a string of murders that has sparked outrage and raised fears freedom of speech is under threat in Muslim-majority Bangladesh."Islamic State fighters assassinate(d) a university teacher for calling to atheism in the city of Rajshahi in Bangladesh," ISIS's Amaq news agency said.Shamsuddin said police had not yet named any suspects, but the pattern of the attack fitted with previous killings by Islamist militants.People close to Siddique said he had never spoken out against religion, but he may have been targeted for his role in leading music and literature groups."As far as I know, my husband didn't have any personal enmity with anyone," his wife, Hosne Ara, told the BBC.Hundreds of university students held protests after news of the murder, marching on the campus and shouting slogans demanding the arrest of the attackers, said local police chief Humayun Kabir."The students were shocked at the latest brutal killing of their teachers," Mostafiz Mishu, a student who witnessed the protests, told AFP."Some 500 of them shouted slogans and joined the marches calling for protection of all teachers and exemplary punishment for the killers."Homegrown Islamist militants have been blamed for killing several secular bloggers and online activists since 2013, most recently in the capital Dhaka early this month.Eight members of banned Islamist group Ansarullah Bangla Team, including a top cleric said to be its founder, were convicted late last year for the murder of atheist blogger Ahmed Rajib Haider.Sakhawat Hossain, a friend and colleague of Siddique at the university, said he used to play the tanpura, a musical instrument popular in South Asia, and wrote poems and short stories."He used to lead a cultural group called Komol Gandhar and edit a bi-annual literary magazine with the same name. But he never wrote or spoke against religion in public," Hossain told AFP.Nahidul Islam, a deputy commissioner of police, said Siddique was involved in several cultural programmes and had set up a music school at Bagmara, a former bastion of an outlawed Islamist group Jamayetul Mujahideen Bangladesh."The attack is similar to the ones carried out on (atheist) bloggers in the recent past," Islam said, adding nobody had been arrested yet.Champa Patel, Amnesty International's South Asia director, condemned the latest killing as "inexcusable", saying it was part of a "gruesome pattern"."The authorities must do more to put an end to these killings. Not a single person has been brought to justice for the attacks over the past year," Patel said.A long-running political crisis in Bangladesh, which is majority Sunni Muslim but officially secular, has radicalised opponents of the government and analysts say Islamist extremists pose a growing danger.Bangladesh authorities have consistently denied that international Islamist networks such as Al-Qaeda or ISIS, which has claimed responsibility for the murders of minorities and foreigners, are active in the country.Ansar al-Islam, a Bangladesh branch of Al-Qaeda in the Indian Subcontinent, this month claimed responsibility for the murder of a 26-year-old law student killed on the streets of Dhaka, according to US monitoring group SITE.Police, however, blamed the Ansarullah group for the murder.