Hefazat-e-Islam Joint Secretary General Mamunul Haque will be cross-examined with other arrested leaders of the group, police say.
Mahbubul Islam, joint commissioner of the detective branch of Dhaka Metropolitan Police, said police would also arrest those whose names would come up during the cross-examination.
All Hefazat leaders with an anti-government stance would be arrested gradually but those not involved in anti-government activities would not face any problems, said high officials of police.
Law enforcers have already identified around 50 Hefazat leaders involved in anti-government activities. They are also trying to identify Hefazat members who came from BNP, Jamaat-e-Islami, and Chhatra Shibir. A drive will be conducted across the country to arrest them.
A Dhaka court placed Mamunul on a seven-day remand on Monday, a day after his arrest in a vandalism case filed with Mohammadpur Police Station last year.
Detective branch officials said Mamunul's political career might end since he had been accused in a number of cases, including 17 under Dhaka Metropolitan Police.
They said his chapter would not be closed soon as he might have to spend the next few years in jail due to these cases.
On Sunday, the police headquarters asked the Criminal Investigation Department (CID) to investigate 23 recent and previous cases filed over Hefazat mayhems. Of those, 15 were lodged in Brahmanbaria and two each in Narayanganj, Chattogram's Hathazari, Munshiganj, and Kishoreganj.
Barrister Mahbubur Rahman, additional inspector general and chief of the CID, said five of the cases had been filed in 2016.
"The CID is technically very sound in carrying out investigations. We are trying to identify the attackers through forensic photos and videos of the mayhems," he added.
He further said the CID had been tasked with the investigations for finding strong evidence so that criminals would not get impunity.
Mamunul was arrested from Jamia Rahmania Arabia Madrasah in Mohammadpur on Sunday noon. He was produced before Dhaka's Chief Metropolitan Magistrate Court on Monday morning.
Public Prosecutor Abdullah Abu said a seven-day remand had been sought for Mamunul in a case filed with Mohammadpur Police Station.
The plaintiff of the case was attacked by a group of men in Mohammadpur as per Mamunul's instructions. The attackers also snatched some dollars and Tk5,000 as well as bank cards from his possession while hurting his religious sentiment, said Abdullah.
But Mamunul's lawyer Syed Mohammad Joynal Abedin Mesbah said there was no clear evidence of the attack.
"Besides, police and detectives grilled Mamunul after arrest. The remand prayer was unlawful and an act of injustice," he said.
After Mamunul's arrest, Hefazat activists attacked police at Mollar Haat in Bagerhat on Monday.
Three policemen, including Kazi Golam Kabir, officer in-charge of Mollar Haat Police Station, Sub-Inspector Thakur Das, and Assistant Sub-Inspector Baharul, were injured in the attack.
They were sent to Mollar Haat Upazila Health Complex for treatment.