Roy was an atheist and had written a book titled The Virus of Faith, which likened religious extremism to an infectious disease. He had come to Bangladesh in February to promote the book during an annual literary festival in Dhaka when he was killed on February 26.

Umar claimed AQIS was also responsible for the deaths of the "blasphemers" Mohammad Shakil Auj, an Islamic scholar shot dead in the city of Karachi in Pakistan last year, the Pakistani blogger Aniqa Naz, who was reportedly killed in a road accident in Pakistan in 2012, and Bangladeshi blogger Rajib Haider, who was killed in a machete attack in Dhaka in February 2013. Roy and Haider were also involved in the Gonojagoron Moncho movement.

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