Dhaka: April 9, 2016. (PCP) Bangladeshi activists and students take part in a rally, demanding the arrest of three motorcycle-riding assailants who hacked and shot student activist Nazimuddin Samad to death as he walked with a friend, in Dhaka, Bangladesh, Friday, April 8, 2016. Police suspect 28-year-old Samad was targeted for his outspoken atheism in the Muslim majority country and for supporting a 2013 movement demanding capital punishment for war crimes involving the country's independence war against Pakistan in 1971. A banned Islamist group in Bangladesh tied to the al-Qaida in the Indian Subcontinent has claimed responsibility for the killing of a student opponent of radical Islam. The killing of 28-year-old Nazimuddin Samad on Wednesday night follows a string of similar attacks last year, when at least five secular bloggers and publishers were killed allegedly by radical Islamists. According to SITE Intelligence monitoring group, Ansar al-Islam, the Bangladesh division of al-Qaida in the Indian Subcontinent, or AQIS, said in a statement posted online on Friday that its members carried out the attack in "vengeance." It said that Samad "abused" God, the Prophet Muhammad, and Islam. It cited three examples from Samad's Facebook page without giving the text of his posts. "This operation was conducted to teach a lesson to the blasphemers of this land whose poisonous tongues are constantly abusing Allah, the religion of Islam and the Messenger under the pretext of so-called freedom of speech," the statement said. It could not be verified independently. Bangladeshi police declined to comment about the statement Saturday, but said they were investigating. Some Bangladeshi media on Saturday criticized the investigating agencies. "One of the reasons we think why the violent radicals continue to succeed in their nefarious plan is the impunity they seem to enjoy," leading English-language Daily Star newspaper said in an editorial. It said that most cases apparently floundered at the investigation stage. "One would have expected the security agencies to have culled enough intelligence in the last three years from those arrested, to neutralize the group," it said. Bangladesh remains a dangerous country for bloggers Even a year after the murder of US-Bangladeshi blogger Avijit Roy, the killers remain at large. Since then, three more bloggers and a publisher have suffered the same fate and many others have fled the country.