Law enforcing authorities in Bangladesh have yet to determine the authenticity of claims from an Al-Qaeda affiliated group that its members are responsible for a number of murders in the country, including that of American-Bangladeshi blogger Avijit Roy.

In the video, called ''From France to Bangladesh: The Dust Will Never Settle Down," al Qaeda in the Indian Subcontinent (AQIS) leader Maulana Asim Umar says his group killed Roy and others because they insulted Islam.

According to SITE, a US website that monitors extremist groups, the video clip was posted to jihadist forums on Saturday. Sources at the Rapid Action Battalion (RAB), the elite paramilitary force in Bangladesh tasked with tackling terrorist threats, told VICE News that they could not confirm the video's authenticity.

In the video, believed to have been made and released by al Qaeda's production house Al Sahab, AQIS leader Umar says: "The battle we are waging is the same — be it against drones, Charlie Hebdo's writings, the policies of the IMF and World Bank, oppression of Muslims or [Indian Prime Minister] Narendra Modi's blood-spitting tongue."

Modi, whose Hindu-dominated party came to power in India after a landslide victory in May 2014, has faced severe criticism for his handling of attacks against Muslims and Christians. Months after Modi took power, al Qaeda announced operations in India and the subcontinent (the subcontinent usually refers to India, Pakistan and Bangladesh).

Umar then claims that his group assassinated "several blasphemers of the prophet and insulters of the Shariah".

Umar claims in the video that the 'blasphemers' include Mohammad Shakil Auj, an islamic scholar shot dead in Karachi of Pakistan last year, blogger Aneeqa Naz, who was reportedly killed in a road accident in Pakistan in 2012, and blogger Rajib Haider, who was killed in a machete attack in Dhaka, Bangladesh, in February 2013.

After Haider's murder in 2013, the Bangladesh police arrested several perpetrators who they claimed were members of a violent Bangledeshi Islamist group, called Ansarullah Bangla, for the murder of blogger Rajib Haider. Ansarullah Bangla was also blamed for a number of similar assaults in which the victims survived, including another in January 2013 on prominent blogger Asif Mohiuddin.

Umar goes on to claim in the video that AQIS militants had also killed "accursed atheist professor of Rajshahi University [Shafiul Islam] and the American citizen Avijit Roy" using a "butcher's knife."

But Bangladesh's police are still standing by their opinion that the murder of blogger Avijit Roy, an American citizen of Bangladeshi origin, on February 26 was the work of Ansarullah Bangla. Ansarullah Bangla claimed responsibility via twitter a few hours after Roy was killed in a machete attack in Dhaka.

Although blogger Washiqur Rahman's name was not mentioned by Umar, his photo was also present in the video beside Roy's.

Shafiul Islam was hacked to death with machetes in broad daylight by unknown assailants last November near the Rajshahi University premises in Bangladesh.

Rahman was also killed in a machete attack in Dhaka in March. Police caught two madrassa students who they believe committed the murder, but are still investigating whether the two have links to Ansarullah Bangla or are connected to Roy's murder.

"We have to investigate whether Ansarullah Bangla is working as the branch of al Qaeda," said Dhaka police chief Muhammad Habibur Rahman to Reuters on Sunday after being asked about the video.

Days after Roy's murder Bangladesh's Rapid Action Battalion arrested Farabi Shafiur Rahman, an Islamist blogger who had threatened Roy online a number of times. However, Farabi is not thought to be linked to the extremist group. Also, a few days after Roy's murder, a team from the US Federal Bureau of Investigation visited Bangladesh to assist local investigators in solving the murder case.

While the FBI investigators have collected DNA samples and other evidence, there has been no breakthrough more than two months after the murder. VICE News learned from Bangladesh police sources that they are currently waiting on the DNA test reports to arrive from the FBI before further progress can be made in the case.

Professor Imtiaz Ahmed of the International Relations department of Dhaka University told VICE News that the video clip does not seem authentic , since "Al Qaeda's wing in the subcontinent is named al Qaeda South Asia and not AQIS."