At least 14 students and a teacher were injured in a knife rampage at a school in the Russian city of Perm. The teenagers who started the assault may have been inspired by the Columbine High School massacre, according to reports. It all started Monday morning when a knife fight broke out between an 11th grader and a former student “on the grounds of personal enmity,” local investigators told RT. The brawl then spilled into a classroom of fourth-grade students.

The teacher and children tried to separate the two, sustaining injuries as a result. That account is challenged by the students, however, who say there was no fight. They say the two teenagers entered a classroom and went directly to the teacher to stab her before attacking other children in the classroom. This echoes an initial report by the mayor’s office, which said the school had been attacked by masked assailants. READ MORE