At least seven students were injured in a bomb blast at a Hefajat leader's madrasa in the port city yesterday.
Police found traces that huge explosives, including more than 30 handmade grenades, had been stored in the room where the explosion took place, said Chittagong Metropolitan Police Commissioner Shafiqul Islam.
Police launched a raid at the madrasa in the afternoon.
They detained madrasa teachers Md Ishaq, Abdul Mannan and Tafsir Ahmed, hostel superintendent Monir Hossain and final-year student Habibur Rahman, ADC Md Shahidullah said as the raid ended around 10:00pm.
Earlier in the evening, law enforcers picked up four others for interrogation.
Jamiatul Ulum Al Islamia Madrasa in Lalkhan Bazar area was established by Hefajat Nayeb-e-Ameer Mufti Izharul Islam Chowdhury, also suspected activist of banned militant outfit Harkatul Jihad al Islami (Huji).
Visiting the hillside madrasa, this correspondent found that all furniture, books, shelves, dresses, dress stands, beds and lockers of the room, which is on the second-floor of four-storey dormitory, were burnt to ashes. The ceiling fan got twisted and the windows were thoroughly damaged.
Witnesses said they saw some blown off human fingers at the spot. One of the injured lost his wrist in the explosion around 11:30am.
The injured include Md Karim, Md Amanullah, Md Jabbar, Md Abdullah, Md Khalek, Nurun Nabi and an unidentified person, all students of fatwa department of the madrasa, sources say.
The madrasa authorities were not cooperating with the police about where the students were taken for treatment.
In the evening, two injured -- Nurun Nabi and Salman -- were picked up while undergoing treatment at the Chittagong Medical College Hospital, said Assistant Commissioner Abdur Rouf of CMP (Panchlaish zone).
The condition of Nurun Nabi was critical as 90 percent of his body was burnt, while Salman suffered 25-30 percent burns, doctors said.
Around 6:00pm, police detained two others -- Md Habib and Jobayer Ahmed -- at Surgiscope Hospital.
The duo was taken to the burn unit of CMCH from Surgiscope Hospital around 7:00pm. Around 50 to 60 percent of their bodies were burnt, said CMCH sources.
Identities of the four were yet to be known.
Mufti Izharul, who is also the madrasa principal, told The Daily Star in the evening that he did not know how many students were injured in the incident.
Earlier in the afternoon, he claimed that the blast occurred from a laptop charger while students were cooking on a stove keeping the room's door shut.
But an explosion from any laptop charger was impossible, says Prof Latiful Haque, head of computer science and engineering of Buet.
A bomb disposal unit of CMP was working at the spot in the evening to see if any unexploded grenade was left.
ADC Md Shahidullah said 100 to 150 shells of handmade bombs were recovered from the madrasa. Police also found three crude bombs and 18 bottles of picric acid.
Locals said they heard a huge bang around 11:30am from the madrasa.
“Hearing the sound, we ran to the madrasa but the students barred us from entering,” said Russel, a college student living in the area.
He saw students taking several injured persons to hospitals. They were not allowing any outsider to help them.
Moulana Abu Saleh, a teacher at the madrasa, said hearing the bang, students and teachers rushed to extinguish the fire by spraying silt and water.
Five students of fatwa department used to stay in the room, he said.
Soon, firefighters from Agrabad fire station rushed to the spot. Fire official Md Yahia said it was a big explosion.
Mufti Izharul, 70, is also the president of Nezam-e-Islam and chairman of an Islami Oikya Jote (IOJ) faction.
The Rab detained him on December 16, 2010 for his alleged link with Huji. He was shown arrested for alleged involvement in the abduction of physician Azizur Rahman.
Abducted in the capital's Mirpur area in September 2003, Azizur had protested militant activities during his stay in Khulna.
Huji chief Mufti Abdul Hannan and several others were also shown arrested in the abduction case, filed by the wife of Azizur.
Names of several militant groups and the IOJ came up during interrogation of the Huji leaders. Izharul got bail on April 5 in 2011.
Mufti Izharul's younger son Musa Bin Izhar is the assistant general secretary of Hefajat-e Islam, a Qawmi madrasa-based Islamist organisation.
Another son, Harun Izhar, is the publicity secretary of Hefajat.
In November 2010, Detective Branch of police arrested Harun Izhar and two of his associates for alleged link with another militant outfit Lashkar-e-Taiba (LeT).
They were planning to attack the US embassy in Dhaka and other establishments, said DB officials.
Harun is now on bail.