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Graduate Research

Mass Killings in Ontario: A Comparison of Domestic and Non-Domestic Killings

Lead Researcher: Ciara Boyd

Photo of Ciara Boyd.

Mass killings, defined as the killing of three or more victims in a short period of time, have received minimal attention in Canadian literature (Leveillee et al. 2009; Mailloux, 2014). The existing research on mass killings has prioritized those that involve single perpetrators who primarily kill strangers, precluding a focus on mass killings that involve primarily family members and intimate partners (Gerard, Whitfield, Porter, and Browne 2016; Capellan and Gomez 2017). In most countries, however, the majority of homicides are committed by someone known to the victim (Brookman, Jones, and Pike 2017; Dawson 2017; Ellis and Hamai 2017; Mazerolle, Eriksson, Wortley, and Johnson 2017; Statistics Canada 2016). Additionally, most mass killings involve male perpetrators who largely target females; however, despite research showing that mass killings are a predominantly male-perpetrated crime, they are rarely recognized as a gendered phenomenon (Marganski, 2019).

Conducted by Ciara Boyd, the purpose of this study is to gain an understanding of what mass killings look like in Canada and explore domestic and non-domestic mass killings through a gendered theoretical perspective. Using a mixed-methods approach, Ciara analyzes 42 mass killings that occurred in Ontario, Canada between 1985 and 2012 and answers the research question: How do victim, perpetrator, and incident characteristics of mass killings involving primarily domestic victims compare to mass killings involving primarily non-domestic victims in Ontario? Ciara’s research begins with a bivariate analysis of secondary data compiled by Professor Myrna Dawson and focuses on a subsample of homicides that involved three or more victims. Following this, Ciara builds upon the quantitative findings with a qualitative content analysis of media coverage on the mass killing incidents, where possible, to identify common themes.

The findings from this research demonstrate that domestic and non-domestic mass killings share similarities (e.g., motivations) and differences (e.g., histories of domestic violence) and draw attention to the toxic masculinity and coercive control that are prominent among many mass killers. This research also introduces a revised motivational typology that builds upon those commonly identified in prior literature and identifies several risk factors for mass killings, such as histories of domestic violence and access to firearms.

To her knowledge, Ciara’s research is the first to use a gendered theoretical framework to compare the characteristics of domestic and non-domestic mass killings and takes a different methodological approach than that utilized in prior mass killing research. It also draws attention to domestic mass killings and provides a starting point for future research to explore domestic and non-domestic mass killings as an extreme form of gender-based violence. Moreover, by identifying risk factors for domestic and non-domestic mass killings, Ciara’s research aids in the development of risk assessment, risk management, and safety planning strategies to prevent mass killings from occurring in the future.


Brookman, Fiona, Helen Jones, and Sophie Pike. 2017. Homicide in Britain. Pp. 320-344 in The Handbook of Homicide, edited by Fiona Brookman, Edward Maguire, and Mike Maguire. Oxford: Wiley Blackwell.

Capellan, Joel and SimonPeter Gomez. 2017. Change and stability in offender, behaviours, and incident-level characteristics of mass public shootings in the United States, 1984-2015.

Dawson, Myrna. 2017. Homicide in Canada. Pp. 348-349 in The Handbook of Homicide, edited by Fiona Brookman, Edward Maguire, and Mike Maguire. Oxford: Wiley Blackwell.

Ellis, Tom and Koichi Hamai. 2017. Homicide in Japan. Pp. 388-411 in The Handbook of Homicide, edited by Fiona Brookman, Edward Maguire, and Mike Maguire. Oxford: Wiley Blackwell.

Gerard, F. Jeane, Kate Whitfield, Louise Porter, and Kevin Browne. 2015. Offender and Offence Characteristics of School Shooting Incidents. Journal of Investigative Psychology and Offender Profiling 13(1):22-38.

Leveillee, Suzanne, Julie Lefebvre, and Jacques Marleau. 2009. Psychosocial Profile of Familicides Committed in Quebec – 1986 to 2000. The Annals of Medical Psychology, Psychiatric Review 167(8):591-596.

Mailloux, Sharon. 2014. Fatal Families: Why Children are Killed in Familicide Occurrences. Journal of Family Violence 29:921-926.

Marganski, Alison. 2019. Making a murderer: The importance of gender and violence against women in mass murder events. Sociology Compass 13(9):1-15.

Mazerolle, Paul, Li Eriksson, Richard Wortley, and Holly Johnson. 2017. Homicide in Australia and New Zealand. Pp. 412-431 in The Handbook of Homicide, edited by Fiona Brookman, Edward Maguire, and Mike Maguire. Oxford: Wiley Blackwell.

Statistics Canada. 2016. Homicide in Canada, 2016. The Daily, 22 November.

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