The perpetrator, student Eric Hainstock, entered the school's main hallway with a revolver and fatally shot principal John Klang.
Principal John Alfred Klang then entered the hallway and confronted Hainstock, who was still armed with the handgun.
When Hainstock was nine, his mother's parental rights were terminated by court order after she failed to pay child support.
In September 2001, the Sauk County Department of Children and Families were called to the residence after he had allegedly kicked his son.
[6] By court-order, Eric was forced to live with his paternal grandmother, before he returned to his father's care in April 2002.
He claimed that his father would make him stand in his bedroom corner with his nose touching a wall and holding one of his legs in the air for long periods.
After Eric shot John Klang, he told police that he had not meant to hurt him; his goal was to confront him and "make him listen" about the bullying.
[6] It later transpired that as a student, Eric had been under medication and using prescription drugs in a bid to treat attention deficit hyperactivity disorder (ADHD).
[6] Hainstock was charged with first-degree murder by the Sauk County District Attorney's office.
[6] In October 2008, Hainstock's supportive cellmate at Green Bay was reassigned without any official explanation.