Three children died under unclear circumstances in the district’s Matlab Dakkhin Upazila on Friday.
The deceased were identified as Abdullah Al Noman, 10, son of Purbokaladi Jaam’e Masjid’s Imam Maulana Zamal Uddin; Ibrahim, 10 of Bhangarpar village; and Rifat, 8, son of Jasim Uddin of Nalua village.
All of them were students of Bhangarpar Madrasa.
Maulana Zamal found them unconscious in his room adjacent to the mosque after Jumm’a prayers.
Swapan Kumar Aich, officer-in-charge of Chandpur Police Station, said the door was bolted from inside.
Locals broke the door and took them to Matlab Dakkhin Upazila Health Complex.
Abdullah and Ibrahim had died before they were brought to the hospital, said Upazila Health and Family Planning Officer Dr AKM Mahbubur Rahman. Rifat, who was still alive, died several minutes later.
Chandpur police chief Jihadul Kabir said the bodies did not have any injury mark.
Police say the cause of death could be known after autopsy.