A Burmese imam is being investigated for possible negligence after 13 children died in a fire at a Muslim school in Rangoon, police said.
Authorities were also quizzing a Muslim teacher in the case, reports said.
Police earlier blamed an electrical fault for the blaze. Most of the children escaped unharmed.
Riot police were deployed to the area as people gathered, concerned that the fire was linked to recent communal violence in other parts of the country.
At least 40 people have been killed since 20 March in the attacks which have mainly targeted minority Muslims.
The school’s imam and a Muslim teacher were being investigated but no arrests had been made so far, Rangoon police chief Win Naing told the AP news agency.
“As the two people in charge, they are responsible for this and we have to take action against them,” he was quoted as saying.
Meanwhile hundreds of people attended the funeral of some of the victims on Tuesday afternoon.
Earlier, police spokesman Thet Lwin said the two-storey building – part of a mosque – in eastern Rangoon sheltered about 75 orphans.
Most of the children escaped by running out of a door after police knocked it open, he said. The school was badly burned.
The Myanmar (Burma) Police Force said on its official Facebook page that the victims had died from burns or smoke inhalation.
One report said all of the victims were boys. The dormitory had locked its doors because of the recent tensions, so the children struggled to escape, reports said.
“The whole country is worried now for Rangoon, and is wondering whether this was a crime,” Ye Naung Thein, a local Muslim leader, told the AFP news agency at the scene.
The fire comes amid an upsurge in violence between Buddhists and Muslims.
On 22 March, a state of emergency was enforced in the central town of Meiktila in the Mandalay region, where violent clashes erupted between Muslim and Buddhist communities after a reported argument at a gold shop.
Many houses and buildings were destroyed in the town and thousands of people, mostly Muslims, displaced.
Curfews have since been imposed in other towns and villages after violence spread.
The violence follows clashes last year in Rakhine state between the Buddhist community and Muslim Rohingyas – a stateless minority group not recognised by the Burmese government.
President Thein Sein has warned that the government will use force if necessary to stop “political opportunists and religious extremists” from fomenting hatred between faiths.