Slain blogger Niladri Chattopadhyay's wife has filed a murder case against four unidentified assailants.
Asha Moni filed the case with Khilgaon Police Station last night, said Zahidur Rahman, sub-inspector of the police station.
Nicknamed Niloy, the 28-year-old victim, who also was a Gonojagoron Mancha activist, was hacked to death by unknown assailants inside his house in the capital in broad daylight yesterday afternoon.
Four men armed with cleavers entered his Goran house in Khilgaon posing as potential tenants and then killed him in his bedroom around 1:15pm, police and family members said.
Meanwhile, Dhaka Metropolitan Police (DMP) deputy commissioner (media wing) Muntasirul Islam has claimed this afternoon that DMP has had much success in the blogger murder cases.
Asked about any evidence, they said these could not be disclosed "for the sake of fair investigation into the cases."
"You cannot say we have no success in investigation into the blogger killing cases," he said talking to journalists at the DMP media centre.
He said an organised criminal gang conducted the murder.
"Some evidences were collected from the crime scene. We are examining them."
"Khilgaon police is investigating the case at the moment. Simultaneously, the detective branch is conducting a shadow investigation while other specialist units are providing technical support," he added.
In a Facebook post on May 15, the slain blogger Niladri mentioned about the police's refusal to accept his application to lodge a general diary about being followed by strangers.
Asked, Muntasirul said, "We noticed that on Facebook. But he didn't specifically mention in which police station the incident took place. Nevertheless, we are probing the matter with utmost importance. If we find any negligence on police's part, we will take legal action against those involved."  
Commenting on the fact that a group has claimed responsibility of the gruesome murder, he said, "Using technology, we are investigating who sent the message from where. We are trying to get information about the sender.
"In short, we are investigating whether their claims are authentic," he said.
With Saturday's murder of Niladri Chatterjee, four bloggers have been killed in a span of just seven months.
However, investigators have yet to make any visible progress into the killings of bloggers -- Avijit Roy, Oyasiqur Rahman and Ananta Bijoy Das -- except the arrest of a handful of suspects.
The law enforcement agencies could not yet arrest the masterminds behind the gruesome killings of bloggers and freethinkers, although they repeatedly claimed that militant outfits had links with the murders.
When this was pointed out, the spokesperson of DMP media wing said, "We successfully solved the mystery of Rajib Haidar murder, arrested the killers and submitted charge-sheet. Two accused in killing of Oyasiqur Rahman Babu were arrested and we are trying to catch others behind. We also identified seven involved in Avijit murder. We haven't been able to arrest them yet, but we are trying."