Inspector General of Police (IGP) Benazir Ahmed has said Hefazat-e-Islam's attack in Brahmanbaria is part of a plan of collective crime.
Though the group is non-political, there was political desire behind their attack, said the IGP.
The impact of their attack will be long-term, said Benazir Ahmed.
He came up with the remarks after inspecting the damaged installations in the district yesterday.
Video footage and photos of the attack incidents are being analysed to identify attackers, said the police chief.
Asked why police failed to keep the situation under control, he said that an investigation is underway to ascertain whether there was any negligence from law enforcers. Action will be taken if any negligence of duty is found.
The IGP has visited establishments damaged during rampage carried out by the leaders and activists of Hefazat-e-Islam in Brahmanbaria from 26 to 28 March in protest against Indian Prime Minister Narendra Modi's visit to Bangladesh.
The police chief began inspecting the damaged installations at 11:45am on Thursday.
He first visited the damaged Allauddin Khan Municipal Auditorium.
IGP Benazir Ahmed also exchanged views with journalists at the Circuit House at 1pm.
Director General of Rapid Action Battalion (RAB) Abdullah Al Mamun, Chief of Special Branch of Police Monirul Islam, Chattogram Range Deputy Inspector General (DIG) Md Anwar Hossain, Brahmanbaria Deputy Commissioner Hayad Ud Daula Khan and Brahmanbaria Superintendent of Police (SP) Md Anisur Rahman were also present.
During the strike of Hefazat-e-Islam on 28 March, various government and non-government establishments in Brahmanbaria were vandalised and set on fire.
Besides, renowned musician Ustad Allauddin Khan's memorial was set on fire during the strike.
Supporters of the strike vandalised Brahmanbaria Khantihata Highway Police Station, the Allauddin Sangeetangan, Sadar Upazila Assistant Commissioner's (Land) Office, Water Development Board Office, Municipality Office, Alauddin Khan Municipal Auditorium, District Council Office, and the home and the office of District Awami League General Secretary Al Mamun Sarkar.
Hefazat activists vandalised and set fire to the houses of Chhatra League President Rabiul Hossain and General Secretary Shahadat Hossain.
They also attacked and vandalised Bank Asia's Brahmanbaria branch and Brahmanbaria Press Club. Also on Sunday, three people were killed in clashes between protesters and law enforcers at the district headquarters and Biswa Road intersection in Sarail.