A 15-year-old student shot and killed a teacher inside a classroom in southern Estonia on Monday, police said, reports GHN based on CNN.
There were four other students inside the classroom, but no one was injured, police spokeswoman Tuuli Harson said.
Investigators are working to determine how the teen got the revolver he used, and why he opened fire, she said.
"School personnel took away the gun and the boy was handed over to the police. All the students are safe. All the children have left school and are with their families," she said. "The police have checked all the floors in the building and nothing suspicious was found."
Estonia Prime Minister Taavi Rõivas described the shooting, which occurred in the town of Viljandi, as a shock for the nation.
"We do not yet know the causes of this incident, but violence is never an acceptable solution. Such things should not happen," Rõivas said in a statement. "We all have a duty to notice a person who is in need of support in struggling with his or her problems. Today's incident is a painful reminder of that."