Ansar Bangla-7, believed to be an Islamist outfit, has claimed responsibility for killing writer and blogger Avijit Roy, the police said on Friday.
The organisation, which has no visible political activities, has given a posting on the Twitter claiming its responsibility of the attack, the Ramna zone assistant commissioner of police SM Shibli Noman said.
The police officer observed that the attacks on writer Prof Humayun Azad and blogger Razib were also carried out in the same manner.
High officials of the detective branch of Dhaka metropolitan police visited the spot at about 1:00pm.
Krishna Pada Roy, deputy commissioner of DB (south), told Prothom Alo though that the detectives were yet to receive any formal directive for investigation into the incident. However, he added, they have started investigation.
None has also been arrested as yet, the police official said.
Earlier, the DB and the Criminal Investigation Department collected evidence from the spot.
Shahbag police officer-in-charge Sirajul Islam also told Prothom Alo that two blood-stained butcher knives and a shoulder bag were recovered from the spot. Handles of the butcher knives were wrapped up by papers, the OC added.
Meanwhile, the body of will be kept on the premises of Aparajayo Bangla on Sunday to show last respect to him, said Keya Barman, wife of Avijit’s younger brother Arijit Roy.
His body will be handed over to Dhaka Medical College for research work, she added.