Police were, however, unable to catch madrasa Principal Izaharul and his son Harun Bin Izahar during the raid, which began at 6:30pm on Monday.
The detainees were identified as madrasa dining superintendent Munir Hossain, three teachers Tafsir Ahmed, Abdul Mannan, Md Ishaq and student Habibur Rahman.
They were held at the institution and an adjacent area for questioning, Chittagong Metropolitan Police’s (CMP) Additional Deputy Commissioner (ADC) Md Shahidullah told bdnews24.com.
Earlier, police had arrested four madrasa students with burn injuries from two private hospitals, where they were undergoing treatment in the port city.
Police cordoned off the madrasa at Lalkhan Bazar and started the raid after top CMP officials visited it hours after a blast rocked and burned one of the rooms of its dormitory earlier in the morning.
After the raid ended at 10pm, Shahidullah said, “We seized 18 bottles of picric acid and detained five.”
Police had earlier said Mufti Izaharul was in the madrasa area until evening. But they could not arrest him.
Asked whether Izaharul had been helped to flee the scene, Shahidullah said, “Raid will continue and the madrasa will be under watch.”
Earlier, police said they found 18 bottles picric acid from the Principal Izaharul’s office at around 8pm during the raid.
ADC Shahidullah said the bottles had ‘Made in India’ and ‘explosives’ written on the bodies.
Earlier, at 11am, an explosion occurred in one of the rooms on the second floor of the four-storey madrasa dormitory. Five were injured.
Madrasa authorities, speaking to reporters later, had claimed an UPS or IPS connected to a computer had blown up.
Explosives were found in various places under the ash after fire-fighters doused the flames sparked by the explosion, CMP Commissioner Shafikul Islam told reporters after visiting the site in the afternoon.
“We are certain that this place housed a large stockpile of explosives. Several handmade grenades were also found. These are very dangerous,” he added.
Meanwhile, ADC Shahidullah at around 6pm told reporters, “We suspect that the explosion took place when bombs were being made. Three live crude bombs and bomb-making materials had also been found from the dormitory.”
No one from the institution was allowed leave once the raid began.
After the explosion, Central Hifazat Nayeb-e-Amir Izaharul, also the chief of Nejame Islam Party, had told bdnews24.com that a laptop or a UPS connected to computer might have exploded.
His son Harun had also made similar claim while speaking to bdnews24.com.
But officials of Detective Branch of Police, CID and bomb disposal unit have collected evidence regarding the explosion, and raw materials to make bombs from the room, where a bomb went off, until afternoon since the blast.
