Two men have been arrested in connection with the killing of secular blogger Niladri Chattopadhyay Niloy.

Of them, Saad-al-Nahin, 26, is the son of Nazrul Haque Nannu, younger brother of State Minister for Labour and Employment Mujibul Haque Chunnu.

The other arrestee is Masud Rana. Both are suspected members of banned militant outfit Ansarullah Bangla Team (ABT), police claimed.

Deputy Commissioner (media) Muntasirul Islam of Dhaka Metropolitan Police (DMP) confirmed the arrests.

Nahin earlier was arrested along with three others in April 2013 for attempting to murder blogger Asif Mohiuddin in January that year. They were later freed on bail.

His father Nazrul, who lives in Kishoreganj, claimed his son's innocence in regard to the Niloy murder.

"I was with my son in Dhaka all the time between August 6 and 8. There is no way he could be involved in the killing," Nazrul told The Daily Star over the phone yesterday.

Niloy, 28, was hacked to death by suspected ABT militants inside his house at Goran in the capital on August 7.

Though Nahin's father said detectives had picked up his son from the capital's Uttara area on Sunday, DB Deputy Commissioner (East) Mahbub Alam of the DMP claimed he was arrested yesterday evening. Masud was arrested around the same time from the capital's Mirpur area, according to police.

A number of suspected ABT operatives, who were arrested earlier, had been kept under surveillance for quite some time and Nahin was one of them, according to a mid-ranking official of the Detective Branch (DB) of police. He preferred anonymity for he was not authorised to speak to the media about this.

The Daily Star phoned State Minister Chunnu several times for his comments but his cell phone was found switched off.

In the Asif Mohiuddin case, the three others to have been arrested with Nahin -- then an Evening MBA student of Dhaka University -- were Kawsar Ahmed, 28, a hawker in Mirpur; Kamal Uddin, 25, a carpenter from Noakhali; and Kamal Hossain, 30, a security guard of Mutual Trust Bank, hailing from Barisal.

Detectives claimed to have recovered several Jihadi books and martial arts uniforms from them.

Nahin had directly taken part in the machete attack on blogger Asif, according to the detectives.

Meanwhile, Motijheel police yesterday summoned Deb Jyoti Rudro and Miraj Nazir, both friends of slain blogger Niloy, to their office but didn't talk to them.

Rudro said they were made to wait from 10:30am to around 1:00pm at the office of the deputy commissioner (Motijheel division) of the DMP but were not asked anything.

"The DC was busy perhaps," said Rudro, adding they were told that they would be summoned again.

In a Facebook post before his death, Niloy said he had gone to Khilgaon Police Station to file a General Diary (GD) seeking security, but was refused. Rudro had accompanied Niloy to the police station.

A police probe committee, tasked with looking into the allegation, submitted its report on Tuesday without quizzing him, according to Rudro.

Niloy's wife Asha Moni, who was inside the house during the killing, filed a murder case with Khilgaon Police Station on the night of the incident against four unnamed assailants.

Later on Sunday, the DB took over the case from Khilgaon police.

IGP FOR DATABASE OF BLOGGERS

Inspector General of Police AKM Shahidul Hoque yesterday asked the DB, the Criminal Investigation Department and the Special Branch of police to make a database of bloggers and keep tabs on what they write in their blogs.

Based on the database, security will be provided to those who are on life threats, he was quoted as saying at the quarterly crime conference of the superintendents of police (SPs) and other police high-ups at the Police Headquarters yesterday.

Earlier on Sunday, the police boss warned secular bloggers against "crossing the limit", which drew flak from different quarters.

The IGP did the same again yesterday. But this time, he also asked the law enforcers to provide counselling support to online writers in order to discourage them from writing anything that might hurt religious sentiments, meeting sources said.