A banned Islamic group in Bangladesh with links to the al Qaeda in the Indian Subcontinent (AQIS) has claimed responsibility for the hacking death of a 28-year-old secular activist. Ansar al-Islam, the Bangladesh division of AQIS, said in a statement posted online Friday that its members carried out the attack against Nazimuddin Samad in the capital city of Dhake.

According to SITE Intelligence monitoring group, the group claimed that Samad was killed out of "vengeance" as he had "abused" God, the Prophet Muhammad and Islam, the Associated Press (AP) reported. Bangladeshi officials reportedly said that they are investigating the claims made by the group.

"We are seriously looking into it," Anisul Huq, Bangladesh's minister for law, said according to CNN. "Unless we are totally sure that this claim ... is authentic, I don't think we will be commenting on it."

In its statement, Ansar al-Islam said that Samad was an "enemy of Allah." The group also listed three of Samad's posts on Facebook as examples of his insults against Islam.

"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, according to AP.

Samad was reportedly attacked with machetes at a traffic junction late Wednesday. The assailants shouted “Allahu Akbar” (God is great) as they attacked Samad, whose family lives in London.

Samad, a student of Jagannath University, used to write frequently against religious extremism. He had written "I have no religion" on his Facebook profile under religious views. In some of his recent posts, Samad had also supported a petition to remove Islam as Bangladesh’s state religion, according to the New York Times.

Since 2013, Bangladesh has witnessed the killings of at least four atheist bloggers and a secular publisher. Police have arrested members of a banned group called the Ansarullah Bangla Team, which is connected to al Qaeda, over those murders, though none have yet been prosecuted.

The group's actions are seen as a threat to free speech in the predominantly Muslim country and a form of retaliation against the 2013 protests that pushed for harsher punishments for former Islamist leaders who were convicted of war crimes.