Workplace murder is the second-leading cause of death on the job and has afflicted many leading companies.
A former employee forced his way into a suburban Chicago factory on Feb. 5, 2001, fired nearly 30 shots from an AK-47, and killed four workers.
On the day after Christmas last year, an employee of Boston-area Edgewater Technology shot seven members of the firm's accounting department, all of whom died.
In the worst mass murder in Hawaii's history, a disgruntled copier repairman murdered seven at a parts warehouse outside Honolulu in November, 1999.
The auto maker suffered shootings during 1994, 1995, and 1996 at factories in Michigan. It has since developed a multidisciplinary workplace-violence response team.
An auto worker shot a co-worker to death at a plant in Sterling Heights, Mich., in December, 1994.
An angry employee shot three of the insurer's executives at a popular lunch spot near its Tampa office in January, 1993.