Sub-Inspector MA Faruq submitted two chargesheets, one for murder and another under explosives act, at Kurhigram Chief Judicial Magistrate's Court on Monday, seven and a half months after the incident.
In the murder chargesheet, 10 were named, but three have already died.
Of the seven alive, four have been named in the explosives case. Three other dead persons were also named in the chargesheet.
The seven accused are 'Jahangir' alias Rajib Gandhi, Saddam Hossain alias 'Chanchal' alias 'Rahul' alias 'Sabuj' alias 'Robi', Reazul Islam alias 'Mehedi', Md Golam Rabbani aka 'Abdulla', Md Mahbub Hasan alias 'Milon', Md Hasan Feroz alias 'Mokhles', and Md Abu Nasir alias 'Rubel'.
According to police, only Rabbani is behind the bars now. The three others are absconding.
Police claimed Jahangir is JMB's northern zone commander.
The accused persons who have died are Khairul Islam aka 'Payel' alias 'Bandhon', Md Shafiul Alam alias 'Sohan' aka Abu Mukadil alias 'Don', and Md Nazrul Islam alias 'Hasan' alias 'Bike Hasan' aka 'Bashir'.
Freedom fighter Hossain Ali, who had converted to Christianity in Kurhigram, was hacked to death near his house in Kurhigram on Mar 22. The killers fled the scene by hurling bombs.
Middle East-based radical group Islamic State claimed credit for the attack.