Dhaka, Bangladesh (BBN)-Rapid Action Battalion arrested Farabi Shafiur Rahman, the key suspect of US-Bangladeshi blogger Avijit Roy murder case, at Dhaka, the capital of Bangladesh, early Monday.
The arrest of Farabi, a self-proclaimed Islamist blogger, was made three days after the killing of Roy.
Detail on the arrest will be elaborated during a press conference later in the day Monday.
On February 26 evening, unidentified assailants hacked to death Roy, 45, whose writings on religion angered Islamist hardliners.
Roy, an atheist who advocated secularism, was attacked when he walked back from Ekushey Moi Bela (book fair) with his wife.
His wife was also sustained severe injuries in the attack.
Roy received death threats after publishing articles promoting secular views, science and social issues on his Bengali-language blog, Mukto-mona (Free Mind).
Farabi is one of the militants with whom Avijit was engaged in debate online.
During their online chat, Farabi gave death threat to Roy.
“Avijit Roy lives in America. So it is not possible to kill him now. He will be killed as soon as he returns home,” Farabi wrote in one of his post.
Roy had said he received threats from Islamist hardliners in Bangladesh last year when his book, The Virus of Faith, was released at a book fair.
"The death threats started flowing to my e-mail inbox on a regular basis," he wrote.
"I suddenly found myself a target of militant Islamists and terrorists. A well-known extremist... openly issued death threats to me through his numerous Facebook entries.
Farabi, a student of Chittagong University, had been arrested for his social media comments supporting the killing of blogger Ahmed Rajib Haider, an activist of Shahbagh movement.
He was later released on bail.
BBN/ASI/AS-02Mar15-1:30pm (BST)