Police filed a case against 220 persons on charges of helping a Juba League murder accused to escape and attacking police at Ramganj upazila in Lakshmipur on Monday.
Of the accused, 20 were named while 200 others were not identified, said Ramganj police station Officer-in-Charge (OC) Lokman Hossain.
Around noon, police arrested six persons, including Karpara Union Parishad Chairman and Awami League President Mujibul Haq, and sent them to jail. However, they could not arrest the murder accused, Mithu.
OC Loman said efforts were on to arrest him.
Earlier on Sunday, police had arrested Mithu in connection with the murder of Juba League leader Saiful Islam in April.
Mujib and his followers had then launched an attack on police and had helped accused Mithu to escape.
Police were able to arrest Mujib and five others from the spot.