|This article does not have any sources. (April 2011)|
A boy that had been expelled from the school, Robert Steinhäuser, was the person who did all the shooting. In anger, he came into the Gymnasium, and shot dead 12 teachers, one secretary, two students, and a police officer.
After a teacher caught him and put him in an empty room, Steinhäuser shot and killed himself. In total, 17 people were killed.