The extremist group thrust itself into spotlight in recent years after attacks on online activists.
An e-mail was sent to the media by ‘Ansar-Al-Islam’, which declared it was the ‘Bangladesh branch’ of al-Qaeda in Indian Sub-continent (AQIS), claiming credit several hours after the killing last Friday.
Police, facing harsh criticisms for failing to catch anyone over the murder after three days, say they are doing everything they can.
Four unidentified youths hacked Niloy to death in front of his wife at their East Gorhan flat, following the murders of three bloggers in the past six months.
They were all murdered in similar fashion - writer-blogger Avijit Roy near the Dhaka University’s TSC in February this year, blogger and online activist Oyasiqur Rahman Babu at Tejgaon in March and secular blogger Ananta Bijoy Das in Sylhet in May.
“It’s possible that an Ansarullah team committed this murder. Detectives have started working on the case. They are looking into all available information to catch the killers.”
The DB’s Deputy Commissioner Mahbubur Rahman told bdnews24.com the e-mail in the name of ‘Ansar-Al-Islam’ was sent from Bangladesh.
“It is possible that one group took part in the killing and another may have sent the mail to hide the murderers or confuse the investigators,” he suspected.
There were 12 wounds by sharp weapons on Niloy's body, most of which were on and around his head.
Forensic experts say the assailants hacked him repeatedly to ensure his death, and added that the process was followed to murder the other bloggers earlier.
Mahbubur Rahman also confirmed that Niloy and other bloggers were hacked to death in the same way.
Ansarullah Bangla Team was banned last year. Its chief Mufti Jashim Uddin Rahmani has been arrested in the case over Rajib Haider’s murder and is being tried.
DB officials had earlier said Ansarullah closely followed global terror group al-Qaeda in its operations.
Two madrasa students, nabbed over Babu’s murder, also confessed that they were inspired by Rahmani’s sermons, delivered at a madrasa at Jatrabarhi, to commit the murder, according to the law-enforcers.
Monirul Islam said they were trying to identify the people who run the e-mail ID and the Facebook page of Ansar-Al-Islam.
The DB joint commissioner said they were also trying to locate blogger Niloy’s laptop and mobile phone, which went missing after his murder.
It is suspected that the assailants took them.
DNA test
The case investigation officer, Khilgaon police Inspector Anwar Hossain Khan presented a tooth, Gaamchha or a hand-made local towel, and a t-shirt, both blood-soaked, before a Dhaka court on Sunday.
He pleaded for DNA testing at the Dhaka Medical College and Hospital.
The court approved and ordered the DMCH authorities to conduct the tests.
Niloy’s wife Asha Moni filed the murder case on Friday night.
Deputy Commissioner Mahbubur Rahman said, “After Niloy was murdered, the t-shirt was found outside the building where he lived. The killers took it off and left it there as the shirt was soaked in Niloy’s blood when he was being hacked to death.”
DB officials visited the East Gorhan flat on Monday morning and spoke with some of Niloy’s neighbours.
The FBI of the United States has offered to help in police probe as the brutal murders of Bangladeshi bloggers sparked international outcry.
A three-member FBI team also held a meeting with the detectives of the DMP on Sunday.
Rahman said they discussed how the US law-enforcing agency would be assisting in the investigation.
He said the FBI team had taken 11 pieces of evidence collected from Avijit Roy’s murder scene to their lab to run tests. “We’ve sought the results from them and asked them to return the evidence.”
Avijit, a naturalised US citizen, was killed in February, several days after coming to Bangladesh. Extremists had threatened him for his secular writing and blogging.
Suspected religious fanatics had also threatened bloggers Niloy and Ananta for their stand against communalism and fundamentalism.
A DB official, asking not to be named, told bdnews24.com they took the murders of four bloggers in six months “very seriously”.
Police came to know the names of seven people involved in Avijit’s murder, said the official. One of the arrestees in Babu’s murder case also gave several other names.
Detectives were doing their best to identify all these people, the official said.