Mass murder is a distinct form of multiple murder which has three defining components: • There are multiple victims of the homicide incident • A limited location for the murders • A limited time period in which the killings occur
For our purposes, mass murder can be defined as: • The killing of three or more people • In one place • At one time
Behavioral Background:Among the varying explanations for mass murder are: Biogenic Factors Psychogenic Factors Sociogenic or Situational Factors Offenders may be involved in an immediate or long standing interpersonal conflict and simply carried out their anger in a particularly violent way.
Dietz (1986) and Holmes’ (1994) combined typology for mass murder offenders:
Family Annihilators: Individual who kills whichever family members are present at the time of the murder incident and who frequently commit suicide at the completion of the incident.
Pseudocommandos: Individuals who have a fascination with firearms and who carry out the offense after an extended deliberation over whether to commit murder.
Set-and-Run Killers: Individuals who employ techniques such as bombing or poisoning so as to allow for the possibility of escape by the offender before the victims are actually killed.
Disciples: Individuals who come under the influence of a charismatic leader and who kill out of a need for acceptance by the leader.
Disgruntled Employee: Individuals who retaliate after having been discharged from their job or for perceived ill-treatment by their employer.
An inherent shortcoming in this consolidated typology is that the combination of motivation, victim/offender relationship and technique for killing that typify some of these categories leaves a classification scheme that is neither mutually exclusive nor particularlyexhaustive in describing cases of mass murder.
Kelleher’s (1997) typology of mass killers represents a more consistent categorization of mass murder cases.
Perverted Love: For this form of mass murder, the offender kills out of a twisted sense of “love”, apparently hoping to spare the victims what the offender views as an unacceptable situation. The victims are most frequently family members.
Politics and Hate: Mass murder is “triggered” by hatred of a particular group or category of people, or for some ideological cause.
Revenge: The offender acts out of a sense of vengeance. This form of revenge is highly personal and deep-seeded, with very specific targets.
Sexual Homicide: Involves mass murder where there is a sexual element to the offense. This is a very rare form of mass murder, and shares many characteristics with serial homicide.
Mass Murder by Execution: Involves the “contract” execution of multiple individuals, or the killing of multiple witnesses to a crime.
Insanity: This form of mass murder involves a mentally ill offender, where the mass murder is a function of the offender’s psychological debility.
Unexplained Cases: Involves cases where the motivation for the offense is unclear, with no apparent precipitating event. These cases often appear to be random acts of murder.
Petee, Padgett and York (1997) suggest a typology consisting of eight categories focusing exclusively on motivation:
Anger/Revenge:Specific Person(s) Target Offender who has directed long-standing anger which motivates him/her toward revenge against a specific person or persons whom the offender believes has wronged him/her.
Anger/Revenge:Specific Place Target Similar to the first category. Here the offender directs his/her anger at a determinate place. Usually the targeted site is significant in that the offender makes some sort of symbolic connection between it and his/her anger.
Anger/Revenge:Diffuse Target In some cases, the offender’s connection to victims or location is either unclear or indirect so that while anger is the motivating factor, the target is essentially diffuse and very often convenient.
Anger/Revenge:Diffuse Target On the other hand, there are some offenders who target categories of people. In these cases, while the intended victims are somewhat more defined in terms of belonging to a particular category of people, they are not specific individuals identified as intended victims.