The recent killings of two teachers are uncomfortable reminders that education can be a risky profession.
In Nevada, middle school math teacher Michael Landsberry was shot on a basketball court by a 12-year-old, who then killed himself.
In Massachusetts, high school math teacher Colleen Ritzer was attacked inside a school bathroom. A 14-year-old is charged.
Experts say the phenomenon of student-on-teacher violence is too often ignored.
Dr. Dorothy Espelage of the University of Illinois recently led a national task force on the issue. The task force found that little has been done to try to understand or prevent these attacks.
A task force survey from 2011 found that 80 percent of teachers reported being intimidated, harassed, assaulted or otherwise victimized at least once during the previous year.