Farabi Shafiur Rahman previously threatened Avijit Roy 's family . Mr Roy hacked to death on Thursday on way back from a book fair . Fundamentalist blogger was arrested in Dhaka earlier today . Comment: Wrote on Facebook : 'When Roy returns to the country , he ’ ll be murdered ' Hundreds of mourners gathered yesterday to pay their respects . Mr Roy 's wife still in a serious condition after trying to save her husband .
Farabi Shafiur Rahman previously threatened Avijit Roy 's family . Mr Roy hacked to death on Thursday on way back from a book fair . Fundamentalist blogger was arrested in Dhaka earlier today . Elite force saw correspondence from Farabi about killing Mr Roy . Wrote on Facebook : 'When Roy returns to the country , he ’ ll be murdered ' Hundreds of mourners gathered yesterday to pay their respects . Mr Roy 's wife still in a serious condition after trying to save her husband .