Encyclopedia of Murder and Violent Crime

Mass Murder

Mass murder is a form of multiple homicide in which four or more victims are slain during a single episode. In December 2000, for example, Michael McDermott, a 42-year-old employee of Edgewater Technology in Wakefield, Massachusetts, opened fire on his coworkers, killing seven of them. In June 2001, Andrea Yates drowned her five children in Houston, Texas.

We can derive some sense of the prevalence of mass killing from the FBI Supplementary Homicide Reports (see Fox, 2000), an incident level database of more than 92% of the murders committed in the United States each year. For the years 1976 through 1999, an estimated 497,030 people were murdered in the United States. Of these, 3,956 were slain in incidents claiming four or more victims. Still, many of these mass killings involve circumstances in which the homicide may not have been intentional, most notably arson resulting in the deaths of large numbers of people. Although ...

—James Alan Fox and Jack Levin