 Story highlights Police say the suspect posted photos of the crime scene 
 
 He also threatened Roy in social media posts, his family said 
 
 Dhaka, Bangladesh (CNN) Bangladesh authorities say they have arrested the prime suspect in the murder of American blogger Avijit Roy who was hacked to death on a Dhaka street last week. Last year, Farabi posted on Facebook: "It's a holy duty of Bangalee Muslims to kill Avijit", the police added.
– The top suspect in the brutal killing of a Bangladeshi-American blogger has been apprehended, Reuters reports. Farabi Shafiur Rahman, who was arrested at a bus stop in Dhaka, Bangladesh, has confessed to threatening blogger Avijit Roy, officials say. "It's a holy duty of Bangalee Muslims to kill Avijit," he wrote on Facebook last year, according to police. Farabi was jailed in the past in connection with an Islamic extremist organization; Roy battled extremism in his writings. Farabi was also arrested last year over social media comments backing another blogger's death, though he was released in that case. That blogger, Ahmed Rajib Haider, was similarly hacked to death, CNN reports.