Police in Bangladesh have arrested three people, including a UK citizen, over the murders of secularist bloggers Avijit Roy and Ananta Bijoy Das.
Both were hacked to death earlier this year. Police say British-Bangladeshi Touhidur Rahman planned the killings.
Mr Rahman, an IT expert, is said to have links with a banned militant outfit, Ansarullah Bangla Team (ABT).
Police say his arrest will provide evidence about a total of four killings of secular bloggers this year.
The Bangladesh Daily Star reported that Touhidur Rahman was also the alleged financier of ABT.
He and two others were detained last night in the Dhanmondi and Nilkhet areas of Dhaka.
Bangladesh is officially secular but critics say the government has not done enough to stop the attacks.
Last week police arrested two other suspected members of ABT over the killing of atheist blogger Niloy Neel.
Mr Neel was hacked to death by a gang armed with machetes at his home in the capital Dhaka.
In March, another blogger, Washiqur Rahman, was hacked to death in Dhaka.
- Founded Mukto-Mona ("Free Mind") blog site in 2000 to champion secular and humanist writing in Muslim-majority Bangladesh
- Bangladeshi-born US citizen on visit to Bangladesh
- Engineer by profession
- Received death threats from Islamist radicals for his writings, family says
- "He was a thinker, he was a man of great knowledge, he was a scientist, he was an engineer" - close friend and Dhaka University professor Anwar Hossain
Ananta Bijoy Das
- Wrote blogs for Mukto-Mona, a website once moderated by Avijit Roy
- Was killed in broad daylight near his home in Sylhet as he headed to work at a local bank
- Was critical of religious fundamentalism and of previous attacks on secular thinkers
- Sweden turned down a visa request from him in April