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Factors Contributing to the Increase of Mass Shootings in the US

Kayla Barnes, Karen Giraldo, Kayla Kearns, Camila Robledo, Angeliki Siafaka, Neoclis Soteriou, Breana Stringer; B/L and NORTHCOM

Week of 04/26/2021

US Mass Shootings from 2009-2021[1]

The United States (US) has averaged a rate of one mass shooting per day since the beginning of this year, totaling 147 mass shootings in 2021, so far.[2] The US is continuing on an upward trend since researchers started tracking the subject of mass shootings after the Sandy Hook Elementary shooting on Friday, December 14th, 2012. Mass shootings in the US especially in 2021 are an issue that must be addressed because the causes could be slightly different than in previous years; therefore, the solution to stopping mass shootings from occurring so often could be different. Multiple factors should be accounted for causing the increasing rates in mass shootings, such as the implications from the COVID-19 pandemic, connections between mental health and gun owners, as well as ideological and political grievances.[3] Reviewing the profiles and motivations of mass shooters will provide insight on potential similarities, differences, and patterns between them.

The national unemployment rate in the US hit a record high of 14.7% in April 2020, as a result of the coronavirus pandemic that led to the crisis.[4] Economic distress can lead people to feel hopeless and experience symptoms of anxiety and depression.[5] Job loss may also lead people to become socially isolated as they lose their workplace social circle. Unemployment and financial distress are very likely to have a much more severe emotional impact during a time of fear and insecurity caused by the global pandemic. The stress and uncertainty about the future in combination with the loss of a support system due to the COVID-19 lockdown measures is very likely to magnify the negative psychological effects of financial distress. The prolonged financial distress and job insecurity may cause or exacerbate mental health and substance abuse problems. As health insurance has been privatized in the US and is often tied to employment, job loss can mean limited access to mental health care and preventive care interventions. The lack of proper mental health care is likely to lead people to feel disappointed and neglected and lose confidence in the government's ability to protect them and willingness to care for them. They may see themselves as victims of unfair treatment and may want to get revenge for their suffering.

At least 40% of all mass shooters in the US between 2000 and 2015 were in financial distress due to unemployment at the moment of the shooting, suggesting that economic distress can trigger a rise in mass shootings.[6] It is likely that the increased economic grievances and the built-up resentments during the COVID-19 pandemic have contributed to the increasingly high numbers of mass shootings and will continue to be an important contributing factor. When Phillip Adams committed the Rock Hill shooting killing six people on Wednesday, April 7, 2021, his career had ended abruptly, he was unable to find employment and it seems that he was under financial distress. Brandon Scott Hole, responsible for the Indianapolis FedEx shooting that left eight people dead on Thursday, April 15, 2021, used to be employed at the FedEx facility and was fired less than six months before the attack. Due to the sharp increase in job insecurity during the COVID-19 pandemic combined with long periods of social isolation, it is also likely that there will be a surge in workplace mass shootings when businesses start to open and people who have been working remotely start to return to work.

Instability throughout the US regarding political and ideological grievances is likely to be a contributing factor to the increase of mass shootings across the US. As such, some individuals may feel angered still by the election of the new administration, furthering their potential hatred towards the government. This is likely to have led to an increase in “panic buying” among pro-gun advocates who fear that the new left-leaning administration may limit their gun rights. An increase in firearms coupled with individuals who are harvesting feelings of anger and resentment is a likely combination for those who are prone to commit mass attacks. This is likely to occur amongst members of the far-right and white nationalist communities. Brandon Scott Hole had a history of browsing websites linked to white supremacist ideologies.[7] The “Brony” culture that Hole was a part of displayed elements of far-right and white nationalism. Aside from frustrations about the loss of his job, Hole may have targeted the FedEx facility due to far-right and white nationalist ideologies learned from online sources, as four of the victims were members of Indianapolis’ Sikh community.[8] Far-right and white nationalist ideologies will likely continue to fuel violence throughout the US and especially more so as individuals seek to reconnect with the world through the use of the Internet. These groups will likely display more hatred towards the government and uphold their white nationalist ideologies as they continue to deny President Joe Biden’s official electoral win as the US President.

Similarly, the rise in hate crimes across the US, particularly those by US law enforcement against African Americans, may be contributing to US instability and the rise in mass shootings. Noah Green, the individual who carried out the Washington DC Capitol police attack on Friday, April 2, 2021, was recently known to have been openly supporting the Nation of Islam.[9] Evidence on Green’s social media supports this claim. According to the Southern Poverty Law Center, the Nation of Islam is deemed as an anti-Semitic extremist group.[10] Green is likely to have targeted law enforcement as a form of retaliation for recent crimes against African Americans, as well as to carry out “suicide by cop,” an ideology that may have been fueled by his psychosis. The ideologies the Nation of Islam uphold may likely have driven Noah Green to carry out the attack, along with other factors.

In addition to the grievances contributed by US political instability, mental health disorders are also a driving factor that has enabled mass shootings to take their toll on a nationwide scale. The US suffers from a severe lack of mental health resources and trained professionals that are highly useful in detecting, assessing, and treating individuals with these disorders before they end up becoming a threat to themselves and the rest of society. Instead, US public rhetoric and support often favors punitive policies and restrictive interventions intended to punish those who are in dire need of psychiatric help.[11] In addition, media sensationalism creates controversial points of view, oftentimes stereotyping and misdiagnosing these individuals. As a result, the lack of support towards mass shooters like Ahmad Al Aliwi Alissa, Noah Green, Philip Adams, and Brandon Scott Hole has ended up costing the lives of innocent civilians. Prevalent background information on these men pointed out a common trait amongst them suggesting that they suffered from some sort of mental illness, whether it was dementia or even depression.

Past pertinent circumstances related to Sandy Hook shooter, Adam Lanza could have served as a learning experience for both law enforcement and medical professionals in knowing that mental health incapabilities can be dangerous for not only the individual but also the rest of society. Just as his mental health problems were left “completely untreated,”[12] so were most of the mass shooters’ from this past year. For instance, ex-NFL player Philip Adams showed signs of mental health deterioration based on his sister’s observations who stated that her “brother’s behavior shifted abruptly in a negative way indicating that he suffered from mental health issues and disabilities.”[13] Pleas and desperation from both Adams and his family urged more mental health resources to be available for him, however, he never ended up receiving the care he needed. Before the Boulder, Colorado shooting, Ahmad Al Aliwi Alissa’s family had expressed that he exhibited aggressive and irrational behavior where he would occasionally lash out at minor issues. More specifically, Allawi’s brother emphasized that he was highly antisocial and paranoid of the thought of other individuals being within such proximity.[14] When observed closely, these symptoms are similar to those exhibited by Lanza, yet there was very little done to help these individuals cope with their ongoing mental struggles. In essence, the US continues to have highly punitive responses towards these individuals, which then creates negative stigmas and narratives that focus on incriminating rather than treating these ongoing issues.

COVID-19 has caused many states to mandate an isolation period to inhibit the spreading of the virus. Many businesses and public places did not have their regular hours of operation and some changed their services altogether. Individuals with compromised immune systems or who live in the same home as someone more susceptible to the fatal side effects of the coronavirus might have to be incomplete solitude to keep others safe around them. Extended quarantines have taken away the socialization skills that people acquire in everyday conversations and have given people more time to engage with harmful thoughts that might not have otherwise come to mind. Individuals who are subjected to extended periods of isolation are at higher risk of many different health consequences such as depression, accelerated cognitive decline, and impaired executive function-- disruption in the self-management of the brain.[15] These side effects of isolation can cause those affected to resort to violence if their processing skills are deteriorating.

On Friday, March 26, 2021, Michael Tucker opened fire on a neighborhood in Memphis, TN, injuring two people and killing three others. Old high school acquaintances described him as quiet, an outcast, and reports state that people saw Tucker walking up and down the street, speaking to himself.[16] These descriptors are similar to the way that many school shooters are outlined; keeping to themselves and having few, if any, friends. Tucker’s motives for this shooting are unknown as he fatally shot himself upon police apprehension, but extended periods of isolation and stress as a result of the pandemic and his perceived exclusion from society likely played a part in his decision to resort to gun violence. Situations exacerbated by the pandemic’s forced isolation periods pose a serious threat in regards to mass shootings and attacks.

Isolation associated with COVID-19 restrictions is likely to have led many individuals to be fixated with the Internet as a means to connect with the world. As such, likely, individuals like Hole and other mass shooters like Phillip Adams and Ahmad Al Aliwi Alissa became fixated with online culture, whether that be one associated with conspiracy theories, religion, or far-right or far-left ideologies. There is an increased likelihood that individuals suffering from some mental health disorders may become more fixated with these online cultures and conspiracies. Ahmad Al Aliwi Alissa suffered from paranoia and fear of being followed by the government. As such, his fears may have been fueled by conspiracy theories linked to the COVID-19 vaccine which may have led him to target individuals receiving their vaccines at the King Soopers grocery store. The lack of instability across the US is likely to further drive individuals into the online world as a means to generate a positive environment for themselves. This can be dangerous as some online communities, along with other factors such as a decline in mental health, can lead individuals to violent tendencies and increase the likelihood of carrying out mass attacks.

There are several strategies targeted towards the issue of mental health that is likely to contribute to a decrease in gun violence throughout the US. These strategies include steps exclusively geared towards addressing mental health, such as the promotion of access to mental health care across the country and training of teachers to recognize signs of mental illness among students. As well as steps touching on mental health that are specifically targeted towards addressing gun violence such as the introduction of red flag laws and mandatory semi-regular mental health check-ins after a gun license is awarded.

A politically controversial step that has been suggested as a means to proactively reduce incidents of gun violence throughout the country is red flag laws. A red flag law is typically a state-level law that authorizes the courts to be able to issue a special type of protection order that allows the police to either temporarily or permanently confiscate firearms from people who are deemed by a judge to be a danger to themselves or others.[17] Should red flag laws be enacted at the federal level it would ensure that the laws are uniform throughout the country and do not vary significantly from one state to the next. This approach would likely be the most effective way to contribute to a reduction of incidents of gun violence, as current state-level gun-control laws can be easily bypassed by traveling across state boundaries. However, it is important to acknowledge the difficulty associated with quantifying the effectiveness of red flag laws as no one can say for certain how many shootings were prevented by such laws.

The implementation of semi-regular mental health check-ins after an individual has been issued a gun license is likely to reduce the incidents of gun violence throughout the US. Continuous re-assessments and screenings of the mental health of gun owners regularly would likely enhance the effectiveness of red flag laws and lead to an overall decrease in the number of guns and gun violence incidents throughout the country. Despite this, the major setback regarding the implementation of semi-regular mental health check-ins after an individual has been issued a gun license is that this would only target legal gun owners who are already registered. This step would do nothing to address the mental health of illegal or otherwise unregistered gun owners, which would likely cause some legal and registered gun owners to feel unfairly targeted by the government.

Greater steps can be taken to promote access to general mental health care across the country. This would likely lead individuals to seek appropriate, nonviolent methods of stress mitigation, therefore preventing a mass shooting. Preventative measures regarding mental health and public safety would likely prevent mass shootings from occurring in the future. This is because around 60% of mass shooters have a history of mental health diagnoses or treatment.[18] Psychosis — delusions and hallucinations — in 172 mass shooters between 1966 and 2020 played some role in 30% of mass shootings.[19] When an individual is equipped with healthy coping mechanisms to deal with stressors, one can assume that they would be able to effectively process negative emotions without harming others. Regular access to medication and other treatment for those who have more serious mental illnesses

A deeper understanding of the warning signs to behaviors that indicate that someone may be on the pathway to violence, a continuum of behavioral markers that an attacker typically displays before an attack, is necessary to detect those who are vulnerable to committing these acts.[20] Advocacy groups, law enforcement, and academic institutions, each have a chance to educate the public on signs such as leakage, which the FBI and researchers have identified as a key warning sign in school shooters.[21] [22] Nikolas Cruz, Stoneman Douglas High School shooter in Parkland, Florida, said online that he was going to grow up to be a “professional school shooter”.[23] While some of these comments may be red herrings or simple attention-seeking behavior, each incident should be investigated fully before being discarded as a false alarm. Knowledge of the prevalence of highly predictive behaviors such as leakage will function as an additional preventative measure, similarly to red flag laws. Real-time artificial intelligence software that combs through publicly available social media and other online content such as Dataminr, can help take part of human error out of the threat-detection process and ensure that troubling rhetoric does not go unnoticed.

While improved access to mental health care and crisis intervention would likely mitigate the risk of mass shootings to some degree, caution must be given to ensure that undue stress on mental health issues as a cause of mass shootings is not perpetuated past the extent that research supports. Research does not indicate that those who are mentally ill are innately dangerous to others, though most mass shooters do have some sort of mental illness, indicating that there is an intervening variable that leads to their decision to conduct a shooting.[24] According to Amnesty International, access to guns, poverty, and social marginalization, particularly of minority groups, are also contributing factors to gun violence in the US.[25] Consequently, over-focus on mental health will likely prevent relevant actors from implementing other strategies aimed at reducing gun violence that is not related to mental health. This may also lead to stigmatization and legal discrimination against mentally ill members of society, the vast majority of whom are non-violent. Therefore, strategies aimed at mental health as a means to decrease the rate of gun violence across the US should be considered as part of a wider strategy that also considers strategies aimed at other contributing factors. Such as strategies aimed at decreasing the overall number of guns in circulation throughout the country through buyback programs, decreasing levels of poverty, and increasing access to educational and job opportunities.

The Counterterrorism Group (CTG) recommends a combined approach to mass shooting mitigation that includes targeted mental health care reform to those in the highest risk categories, investment in threat detection training and computer software, and reevaluation of current firearm legislation. The NORTHCOM and Behavior/Leadership teams at the CTG will continue to work independently and cooperatively to detect and monitor the evolution of gun violence in the United States. The CTG’s Worldwide Analysis of Terrorism, Crime, and Hazards and Threat Hunter programs actively track and catalog detected threats to identify ongoing trends and patterns. This enables strong analysis and reporting that is based on stronger familiarity with the threats posed. The CTG also continues to write reports on threats such as this that provide further analysis to create a more aware public, which is then better guarded against these threats. The Behavior/Leadership team will continue to track behavioral trends which might indicate motivation to commit a mass shooting, to allow stakeholders to generate proactive countermeasures.

______________________________________________________________________ The Counterterrorism Group (CTG)

[3] Explainer, The Gun Violence Archive, N.d.,

[4] Year ends on low note as 787,000 more Americans file for unemployment, The Guardian, December 2020,

[5] Impact of economic crises on mental health, World Health Organization, 2011,

[6] The Economics of Mass Shootings, IZA – Institute of Labor Economics, October 2019,

[7] Brandon Scott Hole: FedEx Shooter was Obsessed with 'My Little Pony' that Has Ties with White Supremacy, International Business Times, April 2021,

[8] FBI says it interviewed FedEx mass shooter last year, Associated Press, April 2021,

[9] Suspect in attack at U.S. Capitol described as average jock whose mental health appeared to quickly unravel, USA Today, April 2021,

[10] NATION OF ISLAM, Southern Poverty Law Center, 2021,

[11] Mental Illness, Mass Shootings, and the Future of Psychiatric Research into American Gun Violence, Harvard Review of Psychiatry, January/February 2021,,_Mass_Shootings,_and_the_Future_of.6.aspx

[12] Adam Lanza’s Mental Problems ‘Completely Untreated’ Before Newtown Shootings, Report Says, The New York Times, November 2021,

[13] 'Nothing makes sense': Former NFL player Phillip Adams shot, killed five people – including family – in South Carolina, police say, USA Today, April 2021,

[14] Brother of Boulder Shooting Suspect Ahmad Alissa Believes He Is Mentally Ill, Newsweek, March 2021,

[15] The risks of social isolation, American Psychological Association, May 2019,

[16] Girlfriend of man killed in mass shooting may never get answers after suspect’s death, FOX 13 Memphis, April 2021,

[17] What Are ‘Red Flag’ Gun Laws, and How Do They Work?, The New York Times, August 2019,

[18] Mass Shooter, Database, The Violence Project, 2021,

[19] Ibid.

[20] 7.0 How Threat Assessment Works: Understanding the Pathway to Violence, Texas State Texas School Safety Center, n.d.,,then%20implement%20the%20violent%20act.

[21] The School Shooter: A THREAT ASSESSMENT PERSPECTIVE, Mary Ellen O'Toole, PhD, n.d.,

[22] “The Concept of Leakage in Threat Assessment,” Behavioral Sciences and the Law, 2011,

[23] Social media paints picture of racist ‘professional school shooter’, CNN, February 2018,

[24] Mass Shootings and Mental Illness, American Psychiatric Association Publishing, 2016,

[25] GUN VIOLENCE – KEY FACTS, Amnesty International, 2021



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