Members of a cell of Ansarullah Bangla Team killed Blogger Washiqur Rahman, said Dhaka Metropolitan Police (DMP) Joint Commissioner Monirul Islam.
He said this at a press briefing in the city's DMP media centre on Wednesday afternoon.
Monirul said the arrested, Arif and Zikrullah, have informed the police during interrogation that they are members of the Ansarullah Bangla Team, a militant outfit, and killed the blogger 15 days after concluding their training.
"At least two to three cells of the militant organisation remain active in the country. The killers of Washiqur were trained in a cell at a house in the city's Jatrabari area. They were tested whether they would be able to operate arms five days before of the killing," he said.
"Later, they led by their big brother Masum conducted the operation and killed the victim on March 27", Monirul said.
"All the accused are students of Hathazari Madrasa in Chittagong. Arif came to Dhaka two years ago after passing Dawra from there while Zikrullah is still a student of the madrasa," he officer depicted.
Members of a cell do not know members of another one and they work by international militant standard, he said and added that Arif joined the Ansarullah Bangla Team by hearing religious sermon in a Mosque after Juma Prayer in 2011.