Mass Homicide and Canada

The federal Liberals make war on guns, not criminals.

This post is by Dr. Caillin Langmann, MD, PhD, FRCPSC, ABEM.

Professor of Medicine, McMaster University.

It may be downloaded from SSRN.


Tragedies as the recent shooting of RCMP officers in Moncton, New Brunswick, raise questions about why these occur and what can be done to prevent these horrible events. There are often many theories raised in the media and by special interest groups but in reality little is known about what are relatively rare incidents.

Mass homicide is often defined as a killing of four or more victims at one location within one event, though the total death count can vary to as little as two people and occur over a number of areas (Knoll, 2012). In Canada, the number of homicide events that occur yearly for which this definition fits is very low numbering within single digits, and usually involves the killing of family members known as familicide. However there have been in the past some notable events, prior to Moncton, such as most recently in Calgary when Matthew de Grood killed five people at a party with a knife. These incidents often due to either the number of deaths, the randomness of the act, or their brutality attract significant media attention and public reaction (Duwe, 2005).

Despite media hyperbole, episodes of mass homicide in Canada are not a new phenomenon of these last couple decades, for example in 1956 John Etter Clark suffering from depression killed seven people on his farm with a single shot .22 rifle. There is little published research done on Canadian episodes of mass homicide, likely due to the small number of events, but it is possible to examine some applicable publications from the United States.

Contrary to what is often reported, episodes of mass homicide are not increasing (Bowers, Holmes, & Rhom, 2010). In fact rates, including mass public shootings, have remained relatively stable since the 1960’s, though media and public attention to these events have increased (Duwe, 2005). As well while the common narrative of a mass homicide is the murderer randomly killing strangers, in fact most mass homicides involve family members (40%), and only 24% involve strangers. Most do not take place in public or at work but rather in residential settings and a quarter are related to criminal activities (Duwe, 2005).

An attempt to profile the perpetrators as well as the reasons behind the attacks has been presented by a number of authors. Common perception is that these people are crazy madmen who suddenly crack and lash out indiscriminately. This is hardly the case. Mass killers plan their assaults for weeks or months, planning in detail where the attacks will occur, how, and who they will kill (Fox & DeLateur, 2013). These people also typically are males and they seem to have a number of characteristics such as depression, resentment or anger as well as blaming others for their problems, social isolation, and a fascination with violent video games and weapons (Bowers, Holmes, & Rhom, 2010). Using these attributes to screen out mass killers is near impossible, as many in society share one or more of those factors and will never go on to violence. Motives for the attack can generally be divided into one of five categories: revenge, power and dominance, loyalty and betrayal, profit, and terroristic.

Methods to mitigate or prevent these attacks have been proposed, but most of them are likely to be ineffectual and some potentially harmful.

Gun control is often on the agenda after one of these incidents, but most experts in this area are of the opinion that such legislation is futile. In particular bans of guns classified as “assault weapons” or “semi-automatic weapons” as well as magazine capacity limitations have been proposed and even enacted in some jurisdictions. Ironically assault weapons are used in less than 4% of mass homicides and an Assault Weapon Ban in the United States was found to have had no effect on the numbers of mass homicides or other types of homicide (Fox & DeLateur, 2013) (Duwe, 2005). Such proposals are usually made by either people who are aware of this statistic but have political motives or are simply people who are unaware and are attempting to be well meaning.

Limiting magazine capacity is often another proposal. These too are likely to be ineffective, for example one of Canada’s notable mass homicides as described above caused a death count of 7 people, three of which were adults, using a single shot .22 rifle. In 2010, after the United Kingdom had banned semi-automatic firearms, Derek Bird a licensed gun owner, drove around in his car and used a bolt action .22 rifle and a double barrel shotgun to kill 12 people – an identical body count to the number of victims in a movie theatre at Aurora, Colorado in 2012 by James Holmes using a semi-automatic AR-15 rifle.

Australia enacted a number of strict firearms laws and bans of semi-automatic rifles, and afterwards having had no mass homicide events using firearms is often cited as an example of how successful laws can be to prevent these attacks. Unfortunately this type of evidence is not that persuasive since New Zealand, a neighboring country with similar demographics and social structure which permits ownership of semi-automatic rifles and handguns, has had no mass homicide events using firearms during the same time frame.

It does appear that people with mental illness with associated violent behavior who are adherent to medication and in treatment reduces their risk of violence (Hall & Friedman, 2013). Conversely psychological background checks either performed at purchase or through licensing may not be very effective. Other than in a small category of bipolar patients, most people with mental illness appear to have a lower rate of violent behavior (Fox & DeLateur, 2013). In fact when 93 recent mass homicides were examined, none were found to be prohibited from possessing firearms by legal definition and only 10 were found to have had prior concerns voiced to a professional. Moreover clinicians are not that adept at predicting violent behavior and currently lack effective screening guidelines and tools that would enable successful screening of potential gun owners (Hall & Friedman, 2013).

While other methods to prevent mass homicide have been proposed such as being proactive when one notices some warning signs such as threats, limiting violence in video games, and media guidelines to limit their coverage to victims rather than the perpetrator, the rare number of mass homicides make it difficult to study any effect of each of these proposals (Fox & DeLateur, 2013) (Duwe, 2005).

Perhaps, as terrible as these events are, instead it might be more relevant to focus on the larger categories of homicide that occur much more regularly in Canada. Currently Canada has around 550 homicides a year, (1.56/100,000) of which there are roughly 170 homicides (0.51/100,000) using a firearm (Statistics, 2013). The rate of homicide has been decreasing dramatically since the 1970s and is down by 64%. In Canada most firearms homicides occur using handguns (62%), by young men ages 18 – 24, and the killer and victim(s) are often considered to be strangers (64%). About half of firearms homicides appear to involve gang related activity, though the real number may be higher.

In 2012 I published a comprehensive study of firearm homicide in Canada spanning 1974 to 2008 (Langmann, 2012). This is the only peer reviewed study where multiple factors contributing to homicide and spousal homicide are examined in the background of gun laws enacted during that period. Demographic and socioeconomic factors were found to be associated with the reduction in firearm homicide rather than firearms laws such as licensing, background checks, restrictions on magazine capacity and control of certain firearms. This study was later supported by another study using different methodology (McPhedran & Mauser, 2013). These results were not necessarily surprising. It is accepted in the study of criminology that an aging population is less violent, as older people tend to have more restraint than younger people. Moreover unemployment and poverty is associated with increased criminality.

Therefore it is suggested that in order to tackle violence and homicide we look towards providing mental health treatment, as well as strategies to target poverty and unemployment and targeting young people at risk of developing criminal behavior.



Bowers, T., Holmes, E., & Rhom, A. (2010). The Nature of Mass Murder and Autogenic Massacre. Journal of Police Criminal Psychiatry, 25, 59–66.

Duwe, G. (2005). A Circle of Distortion: The Social Construction of Mass Murder in the United States. Western Criminology Review, 6(1), 59-78.

Fox, J., & DeLateur, M. (2013). Mass Shootings in America: Moving Beyond Newtown. Homicide Studies, 20(10), 1-21.

Hall, R., & Friedman, S. (2013). Guns, Schools, and Mental Illness: Potential Concerns for Physicians and Mental Health Professionals. Mayo Clinic Proceedings, 88(11), 1272-1283.

Knoll, J. (2012). Mass Murder Causes, Classification, and Prevention. Psychiatry Clinics North America, 35, 757–780.

Langmann, C. (2012). Canadian Firearms Legislation and Effects on Homicide 1974 to 2008. Journal of Interpersonal Violence, 27(12), 2303-2321.

McPhedran, S., & Mauser, G. (2013). Lethal Firearm-Related Violence Against Canadian Women: Did Tightening Gun Laws Have an Impact on Women’s Health and Safety? Violence and Victims, 25(8), 875-883.

Statistics, C. C. (2013). Homicide Survey. Statistics Canada.

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