Six children and a teacher have died after a security guard at their nursery school sprayed them with alcohol and set them on fire, said emergency services. Local newspapers report he was recently fired from the nursery.
Officials said that the accused security guard, who worked as a night watchman at the school since 2008, was suffering from depression.
The attack on the day care facility Gente Inocente (literally "Innocent People", in English) shocked the town of 72,000 in the countryside of Minas Gerais.
According to BBC, Santos poured a flammable liquid over several people inside the day care before starting a fire.
Military police said the man also set himself alight at the building in Janauba, Minas Gerais state.
Nobel Prize in Physics 2017 honours gravitational waves discovery
The first trace at Hanford, Washington state, matched nearly exactly the second at Livingston, Louisiana, 3000 kilometres away. Thorne's contribution in the project was to make key predictions on what the waves will look like and how to identify them.
About 25 people, mostly children, were injured in the attack and are being treated at local hospitals for burns. Some of the patients are being airlifted to a specialised burns unit in the state capital, Belo Horizonte.
Brazilian President Michel Temer called the incident a tragedy. "I want to express my sympathy to the families".
Temer said he understood "this must be an extremely painful loss" for the parents, as he, too, is the father of a school-age child. "But those who have been rescued, the children and the adults as well, we are very hopeful that all will survive", Pimentel told reporters at the scene.
While police continue with their investigations to determine the reason for the crime, Janauba's mayor has decreed seven days of mourning for those who lost their lives.