Media attention is often focused on school violence, such as the April 1999 shooting in Littleton, Colorado, that led to the deaths of fourteen students, including the two gunmen, and one teacher. Just as school can sometimes prove to be a violent place for adolescents, adults often find the workplace unsafe. According to the National Institute for Occupational Safety and Health, approximately one million employees are victims of nonfatal workplace assaults every year and another one thousand employees are murdered while at work. Some of these fatalities include police officers shot while on duty or taxicab drivers killed by a passenger. In many cases, however, the assailant is a current or former coworker.

One of the first incidents of workplace violence to garner national attention occurred in Edmond, Oklahoma. On August 20, 1986, substitute letter carrier Patrick Sherrill murdered fourteen fellow employees at the Edmond...