We considered the three mutually exclusive general attack motivations operationalized by Osborne and Capellan (2017), as well as more specific non-mutually exclusive motivations highlighted in previous research (Lankford, 2013; Silva & Greene-Colozzi, 2019b). In terms of the three general attack motivations, most perpetrators had autogenic motivations (50%); meaning they did not target any specific individuals, and their motivations were self-generated and attributed to their internal/psychological issues (Mullen, 2004). This aligns with the high rate of identified mental illness. Only three attacks (15%) were ideologically motivated (i.e., terrorism-related), and these extremist views were evenly distributed between the three major terrorism categories including: one jihadist-inspired attack, one far-right attack, and one far-left attack. The rest of the shooters had victim-specific motivations (35%); meaning they began by targeting individual(s) they knew, but eventually targeted other victims indiscriminately. When considering other, more specific motivations, the most common was problems at work (40%), including being suspended, fired, or otherwise disciplined. Four of the perpetrators were seeking to garner infamy and personal celebrity from the attack (20%). Only two incidents were rooted in family problems (10%) resulting in a family member being targeted. The Turner Monumental AME Church shooter targeted and killed her mother, and the Cedarville Rancheria Shooter targeted and killed her brother, niece, and nephew. Additionally, the Penn State University shooter was the only one motivated by a relationship problem. However, she did not target her significant other, and she instead targeted random individuals after their recent break-up. 

Most attacks were not impulsive and involved a low to high level of planning (80%). Perpetrators with a high level of planning researched their target location, brought additional firearms / ammunition / other weapons, and/or had an array of protective / tactical gear (Osborne & Capellan, 2017). Of those with high levels of planning were the three incidents involving dyads (i.e., two perpetrators). These three dyad attacks also involved the three ideologically driven perpetrators. In line with the most common motivation, the primary attack location was the workplace (55%). The second most common location was schools (25%). However, a breakdown of the school attacks finds a diversion from popular conceptualizations of school shootings. Two attacks occurred in grade schools and three occurred in colleges. Four attacks (two elementary schools and two colleges) involved perpetrators who were not students and did not attack the school because of any school-related issues. The schools were just random locations to carry out their primarily autogenic and/or mental illness related motivations. The other college shooting (University of Alabama Huntsville) involved a Professor who did not receive tenure (i.e., workplace violence). One attack occurred in a religious institution (Turner Monumental AME Church), but the shooters motivation was not related to the shooting location. Four attacks occurred in open-space locations (i.e., shopping centers and restaurants) with which the perpetrator did not have any professional relationship. Finally, the most common conclusions to an attack involved the perpetrator being arrested (45%) and committing suicide (45%). Six of the nine perpetrators who committed suicide did so before the police even arrived. The least common conclusion was the perpetrator being killed (10%).

Discussion

As very few studies examine female mass shooters, this exploratory research fills an important gap in the literature. In general, this study identified a small population of female mass shooters (N = 20) over a 41-year time period. In other words, this work supports previous research finding female mass shooters are especially rare compared to male mass shooting and female homicide offenders (Fridel & Fox, 2019; Peterson & Densley, 2019). Nonetheless, through descriptive statistics, we offer a clearer picture of the women who carry out mass shootings, their motivations, and the circumstances of these events. Schildkraut suggests, “there are a lot more similarities than differences,” between male and female mass shooters (Jaclyn Schildkraut in Jacobson, 2018, para. 9). This research supports Schildkraut, for instance, finding female shooters are like their male counterparts in their age (i.e., average of 33 years old), mental health (i.e., commonly suggested/confirmed), level of planning (i.e., at least some), and attack conclusion (i.e., arrest and suicide > killed). Findings indicate male and female mass shooters are more closely aligned than female mass shooters and general female homicide offenders. For instance, like male mass shooters, female mass shooters are more likely to be single or divorced, and less likely to have a criminal history, constituting a departure from scholarly findings on female homicide offenders (Jurik & Winn, 1990; Pizarro et al., 2010). In general, three findings standout as providing the most interesting, previously unidentified, and valuable contributions to female mass shooting scholarship.

First, a relationship issue only motivated one shooter, and she did not target the male partner contributing to this grievance. This finding is distinct from general female homicide and mass murder offenders, who are often motivated by relationship disputes (Duwe, 2005; Fridel & Fox, 2019). Relatedly, only one female mass shooter indicated past domestic violence victimization, while research on female homicide offenders finds women often kill their intimate partners with whom they have had a history of domestic violence victimization (Jurik & Winn, 1990). This relationship dispute finding is also distinct from male mass shooters, with research finding one-third of male mass shooters are motivated by either a recent breakup/fight with their partner (i.e., a relationship-based precipitating crisis event), or problems with women at-large (i.e., the incel movement, lack of skills with women, virginity, etc.) (Silva et al., 2021; see also Farr, 2019; Osborne & Capellan, 2017). Similarly, while this research does not include familicides (i.e., a common motivation for female mass murder), it is still important to note these public female mass shooters never targeted their own children. Only two shooters involved family: one targeted their mother and the other targeted their brother, niece, and nephew.

Second, attacks predominately occurred within the workplace, and these attacks were often motivated by workplace problems. This presents a divergence from general female homicide and mass murder targets, and more closely aligns with male mass shooters. While the workplace is one of the most common locations for general mass shootings, more than half of female mass shooters targeted the workplace, surpassing previous findings indicating the workplace is the target in 28-36 percent of general mass shootings (Peterson & Densley, 2019; Silva & Capellan, 2019). Fridel (2021) suggests workplace attacks are often revenge-seeking and based on loose personal relationships. Indeed, our findings support this as workplace attacks often included retaliatory motivations connected to work-related issues. Some research suggests that women, more than men, have greater escalatory tendencies towards other women in the workplace (Winstok, 2006). However, this does not seem to be the case for female mass shooters, as there were more male victim fatalities and injuries than women (see Table 1). Future research should continue to explore the victim-offender relationships in female perpetrated workplace shootings, as well as across female perpetrated mass shootings in general.

Finally, this study finds a higher rate of female mass shooters (15%) work in dyads than general mass shooters (less than 1%) (Peterson & Densley, 2019). Interestingly, all these incidents involved a female working alongside a male counterpart. This aligns with general research finding females are substantially less driven to carry out mass shooting attacks, and these findings suggest that when they do, in some cases, this may be due to male coercion. This finding is particularly relevant to ideologically motivated mass shootings. This work finds all three ideologically motivated female mass shooting attacks involved male co-conspirators, who they were also in a relationship with at the time of the attack. Given ideologically motivated attacks often involve higher levels of planning (Capellan et al., 2019), it is not surprising that ideologically motivated female mass shooters have co-conspirators. Indeed, research suggests ideologically motivated male offenders are more likely to have co-conspirators than any other type of mass shooter motivation (Capellan et al., 2019). Yet, despite this similarity, there is a difference in the proportion of ideologically motivated dyads between men and women. When considering prior research on male mass shooters, approximately 8 percent of ideologically motivated shooters have multiple offenders (Capellan et al., 2019). This study, in contrast, indicates that multiple offenders carried out 100 percent of ideologically motivated attacks. This diverges from general terrorism research, which suggests husbands/boyfriends are rarely the driving force behind radicalized women (Scott, 2016). As such, research should examine the gendered nature of such ideological shootings to understand gendered pathways to ideologically motivated attacks and the dyad relationship.

Limitations

This is one of the first examinations of female mass shooters and there are limitations that should be considered in future research. First, this research only examines mass shooting incidents perpetrated by females in the United States; thus, neglecting this phenomenon as it may exist in other counties. Second, the reliance on open-source data may omit incidents of female perpetrated mass shootings, thereby undercounting the number of incidents that have occurred (Silva & Greene-Colozzi, 2019a). Third, this study included three dyads comprising of female mass shooters alongside male counterparts. Because of their cross-gender nature, it is difficult to parse out a motivation that is specific to the female partner. As such, research should consider exploring dyad relationships further, perhaps through case studies like those done on lone female perpetrators (Fast, 2013; Katsavdakis et al., 2011). Finally, this study is descriptive in nature and does not provide any inferential analysis related to female mass shooters. As an exploratory study, the use of descriptive statistics is appropriate; however, should future research consider hypothesis testing, appropriate comparative and/or inferential statistical methods should follow.

Implications

Despite relatively fewer cases of female perpetrators of homicide, scholars risk losing knowledge about female offenders when they are not uniquely considered (Fox & Fridel, 2019). This research finds female mass shooters in America tend to diverge from other female homicide offenders, particularly when considering relationship dispute motivations and workplace target selection. This is particularly important to consider for those providing guidance on preparedness and de-escalation of workplace conflicts. Women may not comprise a large proportion of mass shooters, but they are overrepresented in workplace mass shooting incidents. Indeed, more research is needed to assess these incidents, particularly the victim-offender relationship in such conflicts and the role gender might play in motivating these incidents.

Relationship grievances were not motivating factors for female mass shooters. Those scholars and practitioners wishing to understand gender and violence may consider this unique departure from female homicide offenders and male mass shooters in their future endeavors, such as theory development. These mass shootings do not stem from intimate partner violence as is often the case for female homicide offenders. Moreover, mass shootings perpetrated by females may not be a reaction to a perceived loss of femininity, as scholars find is the case for many male perpetrated shootings motivated by relationship grievances and their perceived loss of masculinity. Further theoretical development is needed to offer insight on female mass shooting motivations.

Finally, female mass shooters, though displaying many similarities with prior research on male mass shooters, are more likely to have co-conspirators, especially when ideologically motivated. Future research should continue to investigate these patterns and determine what makes female mass shooters unique. As research continues to examine female perpetrated mass violence, evidence-based policies and practices for prevention and response to these incidents should continue to develop. As suggested by this exploratory research, scholars and practitioners have much to gain from examining female mass shooters.