Four young children and their teacher died Thursday in southeastern Brazil after a nursery school security guard sprayed them with alcohol and set them on fire, officials said.

Several others were injured as the blaze spread through the “Innocent People” nursery in Janauba, in Minas Gerais state, early Thursday morning, before it was brought under control by firefighers, according to a statement from state prosecutors.

The guard was hospitalized in serious condition with burns all over his body, the statement said.

Witnesses told the online news site UOL that the man, in his fifties, had been working as a night watchman for eight years.

Minas Gerais police said officers went to the suspect’s home and visited his relatives to try to understand the motive for the attack.

President Michel Temer expressed his condolences via Twitter.

“I am deeply saddened by this tragedy involving children in Janauba, and I want to express my solidarity with the families,” Temer wrote.

As the father of a school-age child, Temer said he understood “this must be an extremely painful loss” for the parents.

Janauba, a city of 70,000, is located some 600 kilometers north of the city of Belo Horizonte.

The office of Janauba’s mayor decreed seven days of mourning.