PUBLISHED
JULY
2020
PUBLISHED
August
2020
United States Secret Service
NATIONAL THREAT ASSESSMENT CENTER
MASS ATTACKS IN PUBLIC SPACES - 2019
U.S. Department of Homeland Security
National Threat Assessment Center
U.S. Secret Service
U.S. Department of Homeland Security
August 2020
is publication is in the public domain. Authorization to copy and distribute this publication in whole or in part is granted.
However, the U.S. Secret Service star insignia may not be otherwise reproduced or used in any other manner without advance
written permission from the agency. While permission to reprint this publication is not necessary, when quoting, paraphrasing,
or otherwise referring to this report, the citation should be: National reat Assessment Center. (2020). Mass Attacks in Public
Spaces - 2019. U.S. Secret Service, Department of Homeland Security.
is report was authored by the following sta of the U.S. Secret Service
National reat Assessment Center (NTAC)
Diana Drysdale, M.A.
Supervisory Social Science Research Specialist
Ashley Blair, M.A.
Lead Social Science Research Specialist
Arna Carlock, Ph.D.
Social Science Research Specialist
Aaron Cotkin, Ph.D.
Social Science Research Specialist
Brianna Johnston, M.A.
Social Science Research Specialist
Steven Driscoll, M.Ed.
Supervisory Social Science Research Specialist
David Mauldin, M.S.W.
Social Science Research Specialist
Jeffrey McGarry, M.A.
Social Science Research Specialist
Jessica Nemet, M.A.
Social Science Research Specialist
Natalie Vineyard, M.S.
Social Science Research Specialist
Lina Alathari, Ph.D.
Chief
Special thanks to the following for their contributions to the project:
Chris Foley, M.S.S.W.
Assistant to the
Special Agent in Charge-NTAC
Katie Lord
Domestic Security
Strategist, Region 2-NTAC
Arlene Macias
Domestic Security
Strategist, Region 4-NTAC
Peter Langman, Ph.D.
Psychologist and Author
RAND Corporation
Homeland Security Operational
Analysis Center
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 2
The U.S. Secret Service’s National Threat Assessment Center (NTAC) is an integral resource for the agency’s no-fail
mission to safeguard this nation’s highest elected ofcials. NTAC’s continuous efforts to ensure the informed
development of prevention strategies through research has also enabled outreach programs and publications that assist
our protective and public safety partners in their missions to prevent targeted violence in communities across the
United States.
This latest study, titled Mass Attacks in Public Spaces – 2019, examines 34 targeted attacks that occurred in public or
semi-public spaces (e.g., schools, places of business, houses of worship, open spaces) from January through December
2019. This report is the agency’s third in a series of annual reports that have examined mass attacks in the United States,
during which three or more individuals were harmed. Since this project began in 2017, there have been 89 mass attacks
involving 92 attackers that occurred in various locations throughout the nation. Understanding the key factors in
preventing these attacks is even more critical this year with the COVID-19 pandemic causing additional stressors in the
lives of our citizens.
To inform prevention efforts, NTAC researchers studied the tactics, backgrounds, and pre-attack behaviors of the
perpetrators to identify and afrm recommended best practices in threat assessment and prevention. Implications
include the identication of potential threats and individuals exhibiting concerning behavior. Strategic development of
interventions and risk mitigation efforts tailored to those specic individuals are also a core aspect of this study. We
encourage our public safety partners to review the information and apply it to their own best practices for providing a
safe environment for communities across the country.
Law enforcement ofcers, mental health professionals, workplace managers, school personnel, faith-based leaders, and
many others all play a signicant role in the multidisciplinary team approach that is the foundation of the eld of threat
assessment. The Secret Service is committed to facilitating information-sharing across all platforms of targeted violence
prevention and public safety. Our longstanding collaborative partnerships with these valuable members of the
community serve to enhance public safety, and strengthen our mandate to keep our nation’s leaders safe.
James M. Murray
Director
The U.S. Secret Service’s National Threat Assessment Center (NTAC) was created in 1998 to provide guidance on threat assessment both within
the U.S. Secret Service and to others with criminal justice and public safety responsibilities. Through the Presidential Threat Protection Act of
2000, Congress formally authorized NTAC to conduct research on threat assessment and various types of targeted violence; provide training on
threat assessment and targeted violence; facilitate information-sharing among agencies with protective and/or public safety responsibilities; provide
case consultation on individual threat assessment investigations and for agencies building threat assessment units; and develop programs to promote
the standardization of federal, state, and local threat assessment processes and investigations.
MESSAGE FROM THE DIRECTOR
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 3
TABLE OF CONTENTS
United States Secret Service
NATIONAL THREAT ASSESSMENT CENTER
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION
Introduction ........................................................................................................................ 5
Overview of the attacks ............................................................................................................. 7
Weapons ............................................................................................................................... 7
Locations .............................................................................................................................. 8
Timing .................................................................................................................................. 9
Targeting ............................................................................................................................ 10
Resolution .......................................................................................................................... 10
Motives ............................................................................................................................... 11
e attackers .....................................................................................................................13
Demographics ................................................................................................................... 13
Employment history ......................................................................................................... 14
Substance use .................................................................................................................... 14
Prior criminal charges ...................................................................................................... 15
History of violence and domestic violence.................................................................... 16
Mental health .................................................................................................................... 17
Psychotic symptoms .................................................................................................. 17
Depression ................................................................................................................. 18
Mental health treatment........................................................................................... 18
Beliefs ................................................................................................................................. 19
Fixations ............................................................................................................................. 19
Online inuence ............................................................................................................... 20
8chan .......................................................................................................................... 20
Online misogyny ....................................................................................................... 20
Stressors within ve years ................................................................................................ 21
Financial instability .................................................................................................. 21
Home life factors ....................................................................................................... 22
Triggering event ........................................................................................................ 22
reats and other concerning communications ........................................................... 22
Behavioral changes ........................................................................................................... 23
Social isolation .................................................................................................................. 24
Elicited concern ................................................................................................................ 25
Conclusion ........................................................................................................................26
Summary and tables .........................................................................................................29
List of incidents ................................................................................................................. 32
Endnotes ............................................................................................................................ 33
INTRODUCTION
While our nation responds to the challenges of the COVID-19 pandemic, we must also contend with the tragic aermath of
mass violence that has impacted our communities. Acts of targeted violence aect cities and towns of all sizes, and impact
individuals in the places where we work, learn, and otherwise carry out our daily activities. e response to this problem, like
many others, requires a community-oriented approach. Although law enforcement agencies plays a central role in preventing
targeted violence, they must be joined by government ocials and policy makers, mental health providers, employers, schools,
houses of worship, and the general public, all of whom have a role to play in keeping our communities safe.
What is
reat Assessment?
In the 1990s, the U.S. Secret
Service pioneered the eld of threat
assessment by conducting research
on the targeting of public ocials
and public gures. e agency’s
threat assessment model oers law
enforcement and others with public
safety responsibilities a systematic
investigative approach to identify
individuals who exhibit threatening
or concerning behavior; gather
information to assess whether they
pose a risk of harm; and identify the
appropriate interventions, resources,
and supports to manage that risk.
Since its founding in 1998, the U.S. Secret Service National reat Assessment
Center (NTAC) has supported our federal, state, and local partners in the
shared mission of violence prevention. NTAC’s research, which informs the
U.S. Secret Service’s approach to countering targeted violence, called threat
assessment, has been made available not only to public safety professionals,
but also the general public. To enhance the impact of these research ndings,
NTAC has delivered more than 2,000 trainings to over 180,000 public safety
professionals. In addition to law enforcement, these events benet mental
health workers, school ocials, and other community stakeholders. NTAC
has further oered direct consultation to law enforcement agencies and other
partners on how to establish threat assessment programs, tailored to the
needs of each community. ese programs are designed to prevent targeted
violence using the U.S. Secret Service’s behavior-based methodologies, which
involve proactively identifying and intervening with individuals who pose a
risk of violence.
United States Secret Service
NATIONAL THREAT ASSESSMENT CENTER
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 5
is report, NTAC’s third analysis of mass attacks that were carried out in public or semi-public spaces, builds upon
Mass Attacks in Public Spaces – 2017 (MAPS – 2017) and Mass Attacks in Public Spaces – 2018 (MAPS – 2018). is
report provides further analysis of the thinking and behavior of mass attackers, as well as operational considerations
for our public safety partners.
1
e study examines 34 incidents of mass attacks – in which three or more people, not
including the attacker(s), were harmed – that were carried out by 37 attackers in public spaces across the United States
between January and December 2019. In total, 108 people were killed and an additional 178 people were injured.
e ndings from this report oer critical information that can aid in preventing these types of tragedies, and assist law
enforcement, schools, businesses, and others in the establishment of appropriate systems to recognize the warning signs
and intervene appropriately. Key ndings from this analysis include:
2
• e attacks impacted a variety of locations, including businesses/workplaces, schools, houses of worship, military
bases, open spaces, residential complexes, and a commercial bus service.
• Most of the attackers used rearms, and many of those rearms were possessed illegally at the time of the attack.
• Many attackers had experienced unemployment, substance use or abuse, mental health symptoms, or recent
stressful events.
• Attackers oen had a history of prior criminal charges or arrests and domestic violence.
• Most of the attackers had exhibited behavior that elicited concern in family members, friends, neighbors, classmates,
co-workers, and others, and in many cases, those individuals feared for the safety of themselves or others.
ese violent attacks impacted a variety of community sectors and were perpetrated by individuals from dierent
backgrounds and with varying motives. However, similar to previous Secret Service research, common themes were
observed in the behaviors and situational factors of the perpetrators, including access to weapons, criminal history,
mental health symptoms, threatening or concerning behavior, and stressors in various life domains. e presence of these
diverse themes shows the need for a multidisciplinary threat assessment approach to violence prevention. Community
professionals, with the proper training to recognize the warning signs, can intervene and redirect troubling behavior
before violence occurs. e Secret Service threat assessment approach encourages assessing each situation as it arises,
and applying the appropriate interventions – which may include the involvement of family members and friends, social
services, mental health professionals, faith-based organizations, or law enforcement when appropriate. is report is
intended to inform those eorts, as we strive together to keep our communities safe.
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OVERVIEW OF THE ATTACKS
Researchers identied 34 incidents in which three or more persons, not including the perpetrator, were harmed during a
targeted attack in a public or semi-public space in the United States between January and December 2019.
3
ree of these
attacks were perpetrated by pairs of attackers. In this section, percentages are calculated based on the 34 attacks.
WEAPONS
Most of the attacks (n = 24, 71%) involved the use of one or more rearms, which included ries, handguns, and a shotgun.
Other weapons used included bladed weapons (n = 6, 18%), vehicles (n = 4, 12%), and blunt objects (n = 3, 9%). ree
attacks involved a combination of weapons, including a rearm and a knife, a rearm and a vehicle, and a knife and glass
bottles. Several incidents involved the attackers bringing weapons to the site (e.g., additional rearms, pipe bombs) that
were not ultimately used.
Attacks Involving Firearms
Percentages shown are out of 24 incidents involving rearms
Seventeen (71%) attacks involved only handguns, six (25%) involved only long guns,
and one (4%) involved both types.
4
In four attacks, multiple rearms were used.
In at least ten (42%) of the attacks involving rearms, one or more of the attackers possessed the rearm illegally
at the time of the incident.
5
In two incidents, an attacker was a minor in possession of a handgun, which is
prohibited under federal law. In the remaining incidents, the attackers had prior felony convictions, had stolen
the rearm, had not obtained a valid weapons license, had a previous involuntary commitment to a mental health
facility, or had another factor present that prohibited them from purchasing or possessing a rearm based
on federal and/or state laws.
6
*Chart totals 37 as 3 attacks used 2 types.
Types of Weapons Used*
Bladed Weapons and
Blunt Objects
Folding knife,
switchblade,
machete,
hunting knife
Hammer,
3-ft 15-lb
piece of metal,
bottle
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LOCATIONS
7
e 34 attacks occurred in 21 states. Of these, 59% (n = 20)
took place at public sites that are freely accessible to the
general population, including sidewalks, restaurants, retail
stores, and a gas station. e remaining 41% (n = 14) were
carried out at semi-public sites, including workplaces, schools,
houses of worship, and military bases. e locations of attacks
in 2019, both public and semi-public, represent a variety of
key sectors in our communities, including education, business,
government, and religion.
e 34 incidents impacted 36 public sites, as two attacks were
carried out at multiple locations.
8
e type of locations most
frequently impacted were places of business/service (n = 15,
44%) and open spaces (n = 11, 32%).
e remaining locations included three educational
institutions (9%), including a high school, a K-12 public
charter school, and a university; two houses of worship (6%);
two military bases (6%); two residential complexes (6%)
9
;
and one bus (3%).
Business/Service Locations
Six service sites:
Automobile service center
Property management co.
Plasma center
Plumbing company
Cemetery
Bank
Four retail sites:
Superstore
Beer and wine store
Gas station
Small supermarket
ree restaurants/bars
One manufacturer
One city municipal building
* With the addition of the new location categories of “Residential Complex” and “Military”
in 2019, the number of open space attacks for 2017 changed from nine to eight as an
attack at an outdoor pool within a residential complex was recoded accordingly.
Public Sites*
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TIMING
e attacks occurred on each day of the week and during every month of the year. Two-thirds of the attacks (n = 22, 65%)
took place during the day and early evening, between the hours of 7:00 a.m. and 7:00 p.m.
Consistent with previous studies on targeted violence, the attacks in this study were frequently short in duration. For
example, one attack targeting a bar district lasted only 32 seconds, yet still resulted in 9 individuals killed and 20 more
injured. Just under half (n = 16, 47%) of the attacks in 2019 ended within ve minutes from when the incident was
initiated. However, over one-third (n = 13, 38%) of the attacks in 2019 lasted 15 minutes or more, a larger percentage than
those in 2017 and 2018. ese incidents included attackers engaging in standos with law enforcement, moving through
oce buildings, and some who moved between locations by car or on foot.
LONGEST ATTACK: On December 10, 2019, at around 12:21 p.m., a 47-year-old male and a 50-year-old female
opened re on a kosher market, killing three and injuring at least three. By 12:30 p.m., 911 received calls regarding
shots red, and by 12:43 p.m., numerous law enforcement personnel responded to the scene. e ensuing gun battle
lasted until 3:25 p.m., when police breached the storefront using an armored vehicle. In the end, both attackers were
killed. e attack lasted 3 hours and 26 minutes.
Attacks by Day of the WeekAttacks by Month
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TARGETING
e attacks resulted in harm to 286 people (108 killed and 178 injured). In three-quarters of the incidents (n = 26, 76%),
the attackers directed harm only at random persons. In the remaining one-quarter of the incidents (n = 8, 24%), the
attacker appeared to have pre-selected specic targets. In all of the incidents involving specic targets, at least one of the
specically targeted individuals was harmed, in addition to at least one random person. e eight incidents involving
specic targets were also all motivated, at least in part, by some type of grievance that was related to a workplace, domestic,
or other issue.
On February 21, 2019, a 35-year-old shot and killed his girlfriend near their residence. e attacker then walked
approximately half a mile to a gas station/convenience store and opened re on random people there, killing the
co-owner of the store and injuring an employee and a customer. e attacker then returned to the scene of the rst
shooting, near his home. He threw away his handgun when he saw the police and was arrested just aer midnight.
ough police called the initial shooting of the girlfriend domestic in nature, they have not released any information to
suggest any connection the attacker may have had to the gas station or any of the victims.
RESOLUTION
10
Almost half of the attacks (n = 15, 44%) ended when the attackers departed the scene on their own. Four attackers called
911 to report their attack and identify themselves as the perpetrator.
Eight attacks (24%) were brought to an end by law enforcement intervention at the scene, including one incident that was
stopped by a private security guard at a school. In ve of these incidents, the attackers were killed by law enforcement. e
remaining attacks ended when the attacker’s weapon became inoperable (n = 5, 15%), as a result of bystander intervention
(n = 3, 9%), or when the attacker committed suicide at the scene (n = 3, 9%). ree additional attackers committed suicide
aer leaving the scene.
11
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MOTIVES
Motives for violence are oen multifaceted. e most
common motives identied for mass attacks in 2019
were related to grievances, mental health symptoms,
and ideological/racial bias.
Grievances
In nearly one-third of the incidents (n = 11, 32%),
attackers were retaliating for perceived wrongs related
to specic issues in their lives. ese grievances most
oen related to some type of personal factor (n = 8,
24%), such as an ongoing feud with neighbors, being
kicked out of a retail establishment, being teased or
bullied, facing an impending eviction, or being angered
and frustrated about college debt and job prospects. e
remaining attacks were motivated by grievances related
to workplace issues (n = 3, 9%) or domestic situations
(n = 1, 3%).
COMPONENTS TO MOTIVE* 2017 2018 2019
Grievances 46% 52% 32%
Personal 2 6 8
Workplace 6 3 3
Domestic 5 6 1
Mental health/psychosis 14% 19% 21%
Ideological/racial bias 21% 7% 21%
Fame 4% 4% 6%
Political 4% 0% 3%
Desire to kill — — 3%
Undetermined 14% 22% 32%
On December 19, 2019, a 66-year-old resident entered the administrative oce of his assisted living facility and
opened re, killing one and injuring two before returning to his apartment and fatally shooting himself. e attacker
had been the subject of complaints for smoking in his apartment, which was prohibited. e complaints resulted in his
rent being increased, and he was warned that he could be evicted if the violations continued.
Related to symptoms of mental health or psychosis
In seven incidents (21%), the attackers’ motives were related to their symptoms of mental illness, including at least three
who claimed to have heard voices commanding them to kill, and others who experienced delusional or paranoid beliefs.
On June 17, 2019, a 33-year-old male drove onto the sidewalk and struck a pedestrian, injuring him. He then drove
down the street and onto the sidewalk again, this time killing a pregnant woman, her unborn child, and her two-
year-old son before crashing into a business, injuring an employee. e attacker attempted to ee but was detained by
bystanders until police arrived. e attacker later told police that just prior to the attack, he heard a voice in his head
that told him to kill methamphetamine addicts and that the baby’s stroller had meth in it.
Ideological/racial bias
Seven incidents (21%) involved attackers who were motivated to violence by extreme or hateful views. Attackers targeted
members of various groups including Jewish, Muslim, Asian, or Hispanic people, as well as police and U.S. soldiers. For
three of these incidents, the attackers were also experiencing mental health symptoms that inuenced their motives.
* The percentages for each year do not total 100 as some attackers had multiple motives.
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On April 23, 2019, during the evening rush hour, a 34-year-old male drove his car through a crowd of pedestrians,
injuring eight at an intersection. He was allegedly targeting two people in the crowd, believing they were Muslim. e
attacker’s car ultimately jumped the curb and hit a tree. He then exited his vehicle, repeatedly said, “I love you Jesus,”
and laid facedown until police arrived and arrested him. e attacker had a history of PTSD and psychotic symptoms.
Nine of the attackers were inuenced by, or showed interest in, past perpetrators of mass violence. Some attackers
documented their admiration of past attackers in their own manifestos or in social media postings, while others spent
time consuming information about past attacks. Five of these attackers referenced other attackers from earlier in 2019
prior to committing their own acts of violence. While three of them referenced other incidents contained in this report,
the remaining two named a mass attacker who targeted public places outside of the United States. One additional
attacker researched a female who was so obsessed with the 1999 Columbine High School shooting that she traveled
from Florida to the Columbine High School area in April 2019. She purchased a weapon, but committed suicide prior
to initiating an attack.
At least six attackers made statements or engaged in prior behaviors that indicated they did not intend to survive their
planned attack. Among these six attackers, four committed suicide aer engaging in the attack.
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THE ATTACKERS
DEMOGRAPHICS
Consistent with previous Secret Service analyses of mass attacks,
nearly all of the attackers from 2019 were born male (n = 34,
92%). ere was one female attacker, and two attackers were
born female but identied as male at the time of the attacks. e
attackers’ ages ranged from 16 to 80, with an average age of 33.
Over two-thirds of the attackers (n = 25, 68%) were under the
age of 35. More attackers in 2019 were in the 15-24 age range
than the previous two years combined.
YOUNGEST: On November 14, 2019, on his 16th
birthday, a student opened re at his high school and
fatally shot two students and injured three others before
fatally shooting himself. e attacker had struggled with
his alcoholic father’s death two years before and was
reportedly having recent problems with his girlfriend.
In the months and days leading up to the attack, some
classmates described the attacker as acting strangely or
appearing depressed while others observed him cracking
jokes and described him as acting normally.
OLDEST: On October 3, 2019, an 80-year-old resident
walked into the lobby of his access-controlled senior
apartment complex and opened re, fatally shooting
one fellow resident, and injuring another and his former
caretaker. About a month prior, the attacker had been
turned down when he asked his former caretaker to
become his mistress, and he had an ongoing feud with the
resident he killed.
According to public information, half of the attackers were
White non-Hispanic (n = 19, 51%), 10 attackers (27%) were
Black/African American, and 5 attackers (14%) were Hispanic.
Two (5%) of the attackers belonged to multiple categories, and
the racial identity of one attacker (3%) could not be determined.
All of the mass attacks previously studied by the U.S. Secret Service - those that occurred in 2017 and 2018 - were carried
out by lone attackers. In 2019, however, three attacks were carried out by pairs of attackers.
For the remainder of this report, all percentages are calculated based on the 37 attackers.
RACE/ETHNICITY
White non-Hispanic 19 51%
Black/African American 10 27%
Hispanic 5 14%
Two or more 2 5%
Undetermined 1 3%
Ages of the Attackers,
2017-2019
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EMPLOYMENT HISTORY
Nearly one-third of the attackers (n = 11, 30%) were known to be employed at the time of the attack, while approximately
the same percentage (n = 11, 30%) were unemployed. ose employed held a variety of positions, including two military
personnel, two fast food employees, a city engineer, a vocal instructor and delivery driver, a chiropractor, a tech support
representative, a defense auditor, a handyman, and a manufacturing assemblyman. e employment status of the
remaining 13 (35%) attackers could not be determined because of limited publicly available information.
SUBSTANCE USE
Nearly half of the attackers (n = 17, 46%) had a history of using illicit drugs (e.g., cocaine, methamphetamine, LSD,
Ecstasy) or misusing prescription medications (e.g., Xanax, Adderall, Vyvanse). For two-hs of the attackers (n = 15,
41%), the use of these substances and/or alcohol and marijuana may have reached the level of abuse causing negative
consequences in their lives, including criminal charges, academic failures, court-ordered treatment, and eviction. One
of the attackers later claimed to have no memory of his attack, alleging he had been drinking heavily at the time and had
blacked out. In this sample of attackers, a signicant relationship was observed between substance abuse and domestic
violence.
12
Ten attackers (27%) had histories of both domestic violence and substance abuse.
On August 4, 2019, a 24-year-old male fatally shot 9 and injured 20 in a popular bar district before being killed by
responding law enforcement. Friends reported the attacker regularly used amphetamines, marijuana, cocaine, and
LSD for at least ve years leading up to the attack. e attacker was found to have had Xanax and cocaine in his
system at the time of the shooting. He also had a history of assaulting women he dated.
Recent Job Loss
Seven attackers experienced, or were about to experience, a job loss prior to their attacks. Four of the unemployed
attackers experienced a job loss in the year prior to the attack. is included two attackers who quit, one attacker
whose contract ended, and one attacker who le active duty military service. Two more attackers were red
minutes or hours prior to initiating their attacks. is included one attacker who opened re immediately aer
being terminated, and another who drove through two towns fatally shooting seven and injuring approximately 25
others two hours aer his termination. Another attacker submitted his two-week notice hours before opening re
at the city municipal building where he worked.
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PRIOR CRIMINAL CHARGES
Half of the attackers (n = 19, 51%) had a criminal history, not including minor trac violations. All nineteen had
previously been arrested or faced charges for non-violent oenses, including drug charges, evading arrest, and reckless
driving. Nearly one-third of the attackers (n = 11, 30%) faced prior charges for violent oenses including assault, robbery,
and domestic violence. In one case, an attacker was arrested and released aer committing felony assault on a deputy sheri
one month before perpetrating his mass attack.
Some of the attackers had extensive criminal histories before reaching the age of 30. Examples included:
On July 9, 2019, a 29-year-old male used a 3.5-inch folding knife to stab three people on a downtown city street in
front of the corporate headquarters for a department store. e attacker had over 30 prior arrests. At the time of
the incident, he was under supervision in the community by the Department of Corrections, who, as early as 2017,
designated the attacker as highly violent with multiple violent oenses and likely to re-oend.
On October 5, 2019, a 24-year-old homeless man used a 15 lb. piece of scrap metal to attack other homeless men
sleeping on the streets, killing four and injuring one. e attacker had a history of at least 14 prior arrests, four of
which occurred within a year of the attack. His three most recent assault charges were dropped because the victims
stopped cooperating, and another charge was dismissed due to a technicality. At the time of the oense, the attacker
had two warrants for failure to appear in court and at a court-appointed program.
On January 29, 2019, a 29-year-old male injured four people by driving his vehicle into a homeless encampment.
e attacker had over 10 prior arrests and numerous probation violations. About two months before the attack, he
assaulted two homeless people while intoxicated and was arrested shortly aer eeing the scene in his car. He was
released on pretrial supervision aer receiving multiple charges, including DUI, driving on a suspended license, and
battery. He was later charged with a felony related to obstruction and resisting arrest. He was released back on pretrial
supervision. At the time of the attack, he had an active warrant for missing a court date ve days prior.
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On October 6, 2019, a 23-year-old male opened re with an accomplice inside a bar, killing four and injuring ve. e
attacker had a history of at least 10 prior arrests for various oenses, including illegally carrying a concealed weapon,
drug possession, and failure to appear for court. At the time of the attack, he had pending felony cases for possession of
a controlled substance, eeing from police, and tampering with a motor vehicle.
Several attackers engaged in criminal behavior that resulted in contact with police but did not always result in an arrest.
One attacker had over two dozen contacts with a local police department due to his involvement in disputes with his
neighbor, ghts, and driving without a license and/or insurance. In another case, an attacker had law enforcement called on
him at least four times over a period of nine months because he red shots from his residence; a report was never made for
any of the calls. Police contacted the mother of a third attacker aer her son sent another student a message saying he was
thinking of committing suicide-by-cop and taking hostages. Police were also contacted about a fourth attacker aer he told
a peer that he fantasized about slitting her throat.
HISTORY OF VIOLENCE AND DOMESTIC VIOLENCE
Nearly half of the attackers (n = 17, 46%) had a history of violence toward others, though only some of them faced criminal
charges for the behavior. irteen attackers (35%) committed prior acts of domestic violence, only seven of whom were
charged for those acts. is nding is consistent with the rates of domestic violence seen in attackers from 2017 (32%) and
2018 (30%).
On February 15, 2019, a 45-year-old male shot and killed four co-workers and injured one other, aer he was red
during a disciplinary meeting. He proceeded to chase the injured employee into an adjacent warehouse, where he
killed another co-worker. e attacker then opened re on responding police ocers before he was fatally shot by
police. Despite being the subject of a protective order by an ex-girlfriend based on allegations of stalking, the attacker
continued to harass her. is continued harassment resulted in a ne and a supplemental restraining order. He also
assaulted another ex-girlfriend, on one occasion stabbing her multiple times with a butcher’s knife in the back and
neck. For this assault, he served 3 years of a 10-year prison sentence. Both former girlfriends said he would threaten
them in order to manipulate and control them.
While a history of domestic violence does not precede every mass attack, the frequency with which these crimes are
observed should highlight for law enforcement and other public safety professionals the importance of providing
appropriate interventions in scenarios involving physical or verbal abuse directed at partners. As a reminder, federal law
prohibits the possession of a rearm by any person who:
• is subject to a court order restraining the person from harassing, stalking, or threatening an intimate partner or child
of the intimate partner; or
• has been convicted of any crime of domestic violence.
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* The numbers reported for the subtypes of psychotic symptoms do not equal the total number of attackers
with psychotic symptoms as attackers often had multiple types of these symptoms.
MENTAL HEALTH 2017 2018 2019
Any mental health 64% 67% 46%
Psychotic symptoms* 32% 37% 30%
Hallucinations 6 1 7
Paranoia 6 9 6
Delusions 2 5 4
Depression 14% 37% 24%
Suicidal thoughts 21% 30% 14%
MENTAL HEALTH
According to estimates from the Centers for Disease Control and Prevention (CDC), over half of the population in
the United States will be diagnosed with a mental health disorder at some point in their lifetime, with 20% of adults
experiencing mental health symptoms each year.
13
Of the 37 attackers in this study, at least 17 (46%) experienced mental
health symptoms prior to their attacks.
e vast majority of individuals in the United States who display the symptoms of mental illness discussed
in this section do not commit acts of crime or violence. e symptoms described in this section
constitute potential contributing factors and should not be viewed as causal explanations for the attacks.
e most common symptoms experienced by
the attackers in 2019 were psychotic symptoms
(n = 11, 30%), including hallucinations, paranoia,
and delusions. e next most common symptom
was depression, which was exhibited by one-
quarter of the attackers (n = 9, 24%). Five attackers
(14%) had a history of suicidal thoughts.
Some attackers experienced multiple types of
mental health symptoms. For example, one
attacker experienced paranoid delusions and also
experienced symptoms of depression, suicidal
thoughts, and aggression.
Psychotic Symptoms
While the percentage of attackers who experienced any mental health issue in 2019 (46%) was lower than the percentages
from 2017 (64%) and 2018 (67%), the percentage of attackers who experienced psychotic symptoms, specically, was
about the same in each year.
14
A third of the attackers (n = 11, 30%) in this study experienced these symptoms.
Compared to the rates of depression and anxiety in the general population, psychotic disorders (e.g., schizophrenia)
are relatively rare occurences. It is estimated that around 3.5% of the population experiences symptoms of psychosis.
15
In this sample, the age of onset varied, with some attackers experiencing symptoms in adolescence while others began
experiencing symptoms later in life. e types of psychotic symptoms experienced by the attackers included:
Hallucinations, or sensory perceptions that seem real but occur without any external stimulation. e most common
type of hallucination is auditory (e.g., hearing voices).
Paranoia,
16
or feelings of pervasive distrust and suspiciousness that one is being harmed, deceived, persecuted, or
exploited by others.
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Delusions, or false/idiosyncratic beliefs that are rmly maintained despite evidence to the contrary.
On December 28, 2019, a 37-year-old male entered a rabbi’s house, where a congregation had just nished
celebrating the last night of Hanukkah. He attacked congregants with a machete before being drawn outside and
eeing. Five congregants were injured with one eventually dying from his wounds. e attacker had a long history
of mental health issues, including a diagnosis of schizophrenia. His symptoms included paranoia and auditory
hallucinations that sometimes commanded him to take certain actions. He also displayed a number of compulsive
behaviors, such as washing his hands multiple times a day with bleach, wrapping his items in plastic, washing dollar
bills, and pouring bleach in front of car wheels.
Depression
One-quarter of the attackers (n = 9, 24%) experienced symptoms of depression prior to the attack. Symptoms of
depression included insomnia, changes in appetite, feelings of sadness, diculty concentrating, and thoughts of suicide.
While psychotic symptoms remain the most common mental health symptom observed among mass attackers in
2019, it is worth noting that the two adolescent attackers in this report who targeted K-12 schools are reported to have
experienced symptoms of depression prior to their attacks. Symptoms of depression in adolescent attackers were also
described in a previous U.S. Secret Service study, titled Protecting America’s Schools: A U.S. Secret Service Analysis of
Targeted School Violence,
17
which found that two-thirds of the student attackers exhibited some sign or symptom of
depression prior to their attacks.
On May 7, 2019, a 16-year-old student and an 18-year-old student entered a classroom in their high school, where
they fatally shot one and injured six. One of the attackers was reported to have experienced multiple symptoms
of depression, including self-harm, suicidal ideations and statements, and negative self-talk that he mistook for
command hallucinations.
Mental Health Treatment
Nearly one-third of the attackers (n = 12, 32%) were previously diagnosed with or treated for a mental health condition.
Only ve attackers with histories of mental health symptoms had no known history of diagnosis or treatment based
on open sources. e timing of when attackers were rst diagnosed or began receiving treatment ranged from early
childhood to within months of the attack.
e treatment received by the attackers varied widely and was not always sustained. e type of treatment received
ranged from counseling or medication management to involuntary hospitalization. is highlights the importance of not
only engaging those with mental health symptoms in treatment, but also ensuring that they maintain access to treatment
over time.
On August 31, 2019, a 36-year-old male opened re at pedestrians and vehicles from his car, fatally shooting 7 and
injuring 25 others. He had contacted both 911 and the FBI before his attack and claimed that there was a conspiracy
(or multiple conspiracies) to cyberstalk him, kidnap him, make him watch child pornography, and kill him. He had
a history of mental health issues, paranoia, and violent acts against himself and others, which caused him to be
institutionalized in 2001, 2006, and 2011.
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BELIEFS
One-quarter (n = 9, 24%) of attackers held ideological beliefs, some of which were hate-focused and associated with
violence. ese beliefs were oen multifaceted and covered a range of issues, including anti-Semitism, white supremacy,
Nazism, xenophobia, antifascism, jihadism, and anti-immigration. e prevalence of diverse ideological beliefs among
mass attackers studied by the Secret Service has remained between 24% and 30% from 2017 to 2019.
On April 27, 2019, a 19-year-old male entered a synagogue and opened re, killing one and injuring three
others. Nearly a year and a half prior to the attack, the attacker began to explore and post anti-Semitic and white
supremacist online content. His posts culminated in a seven-page manifesto where he explicitly documented his
hatred for other races, his willingness to violently ght for his beliefs, and the justications for his actions.
FIXATIONS
Seven (19%) of the attackers exhibited a xation, dened as an intense or obsessive preoccupation with a person, activity,
or belief to the point that it negatively impacted aspects of their lives. Fixations oen carried an angry or emotional
undertone and usually involved one of several themes, including ideological beliefs, an intense interest in death or
violence, preoccupation with previous mass attackers, and obsession with a previous romantic partner. Behaviors
associated with xations included stalking and/or harassment, violent verbal or online rhetoric, and writing manifestos.
ese xations were observed by others and, in some cases, extended for a number of years. One attacker was fascinated
with rearms, violence, death, and suicide-by-cop. ose who knew him were well aware of his interest. At one point,
aer telling a counselor that he dreamed of carrying out a school shooting, he was expelled from school. Other attackers
kept their xations to themselves.
On April 30, 2019, a 22-year-old male entered a university campus he had previously attended. Upon entering a
classroom, the attacker killed two students and injured four more. At least a year and a half prior to the attack, the
attacker began to watch videos of previous school attacks and specically researched the 2012 school shooting in
Newtown, CT which resulted in the deaths of 20 children and 6 sta. He spent hours a day conducting these searches.
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ONLINE INFLUENCE
e internet allows individuals from across the globe to virtually connect and share ideas in a profound way. is
connectedness has also allowed those with fringe or extremist ideologies to converge and promote their beliefs to a wider
audience. Some of the attackers in this study were inuenced by hateful content shared on “chan sites” and other websites.
8chan
For two of the attackers in this study, their actions were inuenced
by content they consumed online related to 8chan, an imageboard
website. An imageboard is a type of online forum where images
are posted with accompanying text that stimulate comments
and discussion. e attackers’ consumption of 8chan material
inuenced their beliefs, as both attackers described being inspired
by the actions and writings of the individual who attacked
mosques in New Zealand on March 15, 2019. ey described this
inuence in their manifestos, which were posted to 8chan prior to
their attacks.
On August 3, 2019, a 21-year-old male drove over ten
hours from his home and opened re at individuals
shopping at a large chain retail store. He specically
targeted the Hispanic community, killing 23 people and
injuring 22 others. e attacker had actively posted on
his Twitter account and on 8chan about his xenophobic
anti-immigration beliefs. In the minutes before his attack,
he posted a manifesto on 8chan in which he outlined his
political and economic reasons behind the attack, and
what he described as the “Hispanic invasion of Texas.”
He encouraged others to spread his message if his attack
was successful.
Online Misogyny
While much of the extremist rhetoric espoused online is racially or ethnically based, another concerning online community
involves men who use digital platforms to voice misogynistic views and general animosity toward women. Incels, a term
referring to those who are involuntarily celibate, are mostly heterosexual males who view themselves as undesirable to
females and therefore unable to establish romantic or sexual relationships, to which they feel entitled. ose who self-
identify as incels have gravitated toward the Internet to promote their ideology.
In this report, two attackers shared traits consistent with incel ideology, including an intense animosity toward women. For
example, one attacker oen referred to women by derogatory slurs and, while in high school, had composed a “rape list” of
girls who had turned down his advances. He also fantasized about sexual violence against women and had choked females
on multiple occasions in adolescence.
Chan Sites
e rise of 4chan and 8chan (aka Innitechan
or Innitychan), known collectively as “chan,”
has further propagated violent ideologies online.
Chan sites are largely unregulated, with few
rules and moderators to enforce them. Users
are able to post anonymously, and a formal
registration process is not required. Because
of this, it is dicult to block or remove a user
for an extended period of time.
Chan sites have allowed for the dissemination of
new extreme ideologies such as QAnon, an alt-
right movement promoting multiple government
conspiracy theories, which originated on 4chan in
2017. 8chan in particular has been linked to white
supremacy, neo-Nazism, the alt-right, racism,
anti-Semitism, hate crimes, child pornography,
and multiple mass shootings. Aer several mass
attacks in 2019 linked to this platform, it went
oine in August 2019 and was re-launched in
November 2019, rebranded as 8kun.
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ose tasked with assessing threats and preventing violence will benet from familiarizing themselves with the incel
movement. Special focus should be given to understanding the traits and terminology of this belief system, such as the
“manosphere,” a term for the websites and digital forums on which these views are shared. While some discussions in the
manosphere involve topics of “men’s rights” and “fathers’ rights” that sometimes dehumanize women, other discussions
attempt to legitimize violence against women outright.
Another emerging philosophy, not only within incel and manosphere forums but also within forums related to far-right or
alt-right communities, is the concept of “the red pill,” which was taken from a popular movie. e main character in that
movie is given the choice between a red pill and a blue pill. ose who take the red pill choose to wake up to the harsh truths
of reality, while those who choose the blue are shielded from the truth and remain oblivious and complacent. One attacker
in this study referenced “redpill threads” in a post about his manifesto on 8chan before he killed one and injured three more
at a synagogue.
STRESSORS WITHIN FIVE YEARS
Most of the attackers (n = 32, 87%) had at least one signicant stressor occur within the ve years leading up to the attack,
and for 30 (81%) attackers, the stressor(s) experienced occurred within one year. Some attackers experienced a persistent
pattern of life stressors that lasted several years, up to the time of their attacks. ese stressors, among others, included
signicant medical issues, turbulent home lives, and strained relationships. In addition to the criminal charges described
earlier, stressors aected dierent areas of the attackers’ lives, including:
• Family/romantic relationships, such as a break-up, divorce, physical or sexual abuse, family health issues, the death
of a loved one, or dealing with protective orders led against them by their partners.
• Social interactions, such as the ending of friendships or being bullied in school.
• Work or school issues, such as disciplinary actions, conicts with colleagues, losing a job, failing classes, or being
expelled from school.
• Contact with law enforcement or the courts that did not result in arrests or charges, such as law enforcement
responding to reports of peeping through windows, ghts, or law enforcement being called for neighbor disputes.
• Personal issues, such as evictions, homelessness, struggles with sexuality, being assaulted, or physical injury.
Financial Instability
Half of the attackers (n = 20, 54%) had a history of nancial instability within ve years of the attack. Indicators of such
instability included an inability to sustain employment, loss of income, and being evicted.
On May 29, 2019, a 65-year-old male shot three people at a plumbing company, then stole a victim’s car and ed the scene.
Aer a gun-battle with o-duty police, during which a deputy was severely injured, the attacker was found hiding under a
boat approximately one mile from the business. As ocers approached, the attacker shot and killed himself. Years prior, the
attacker fought the city over property he owned that was to be condemned. Unable to aord the costs involved, the attacker
ultimately lost the property. In 2009, when the owners of the plumbing company purchased the lot behind their store, they
allowed the attacker to live there for free on the condition that he kept it clean. He stayed there in a van or small shed, and
the owner would oen bring him food and water. To make money, the attacker sold water heaters and scrap metal and
over time the property became lled with vehicles, barrels, and debris. When asked to keep the property clean, the attacker
refused. ree months before the attack, the owner secured an eviction in court, but he delayed the notication. e
attacker was served with eviction papers by the sheri’s department around 48 hours before beginning his attack.
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Home Life Factors
Many of the attackers had a history of negative home life factors. For about one-quarter (n = 9, 24%) of them, this included
some form of adverse childhood experience, such as the death of a parent; suering abuse; or exposure to alcoholism, drug
addiction, or domestic violence. Fieen of the attackers (41%) had an unstable home life at the time of the attack. is was
evidenced by evictions, homelessness, the absence of a parental gure, and a parent struggling with mental health symptoms.
Seven of the attackers were homeless at the time of the attack, and two more had received a second or third notice regarding
an impending or possible eviction.
On January 23, 2019, a 21-year-old male entered a bank, made the ve women inside lie facedown on the oor, and
fatally shot each one. He then called 911 and stated that he had shot ve people. e attacker was taken into custody
aer a nearly two-hour stando with police. e attacker had experienced several negative home life factors growing up.
His parents divorced when he was young and his father remarried and divorced again during the attacker’s childhood.
Both parents had signicant nancial issues with liens, foreclosures, and court judgments against them. His father had
a number of criminal charges and was at one point delinquent in his child support to two dierent women. According to
friends from high school, the attacker had a dicult relationship with his father, and his mother did not take his mental
health problems seriously.
Triggering Event
Ten (27%) of the attackers appeared to experience a triggering event prior to perpetrating an attack. is included having
their rent increased, being evicted, being kicked out of a business, and being red from a job. For eight (22%) of these
attackers, the triggering event appeared directly related to who they targeted or where they perpetrated the attack. For the
remaining attackers, one attacked random individuals unrelated to his workplace aer he was red, and the other attacked
former coworkers aer a judge issued a second eviction notice.
On October 3, 2019, a 64-year-old male opened re at a cemetery where he formerly worked, killing one and injuring
two others. He had threatened his apartment’s management and le multiple incendiary devices at or near his
residence. e attacker, who had a history of concerning behaviors, was red seven years prior and sought revenge
against his former employer due to the subsequent nancial hardships he faced. e attack appeared to be triggered by
his eviction from his apartment.
THREATS AND OTHER CONCERNING COMMUNICATIONS
Two-thirds of the attackers (n = 24, 65%) engaged in prior threatening or concerning communications. Many had
threatened someone (n = 16, 43%), including threats against the target in eight cases (22%). e attackers who made
threats against someone they later targeted ranged from those who threatened a specic individual (e.g., a co-worker)
to those who threatened an entire group (e.g., Jewish people, the homeless).
On August 4, 2019, a 24-year-old male opened re in a busy nightclub district, killing 9 (including his sibling) and injuring
20 before ocers shot and killed him. e attacker had a history of concerning communications, including harassing
female students in middle and high school, making a hit list and a rape list in high school, telling others he had attempted
suicide, and showing footage of a mass shooting to his girlfriend. Months before the attack, he went to bars and would tell
his friends that he could have “done some damage” there.
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Over half of the attackers (n = 21, 57%) made some type of
communication, in the form of written, visual, verbal, or online
statements, that was not a threat but should have elicited concern in
others. ese concerning communications included making paranoid
statements, sharing videos of previous mass attacks, vague statements
about their imminent death, and one attacker telling his school counselor
that he had a dream about killing his classmates.
BEHAVIORAL CHANGES
Two-hs of the attackers (n = 15, 41%) exhibited changes in behavior that
were observable to others, including new or increased substance use, feelings
of depression, isolating from family and friends, engaging in self-harm,
spontaneously quitting a job or withdrawing from school, and changes in
appearance. ese changes in behavior were observed by family members,
friends, and co-workers. In seven of these cases, the behavior changes
occurred within a year of the attack.
On October 5, 2019, a 24-year-old homeless man used a 15 lb. piece of scrap metal to attack other homeless men
sleeping on the streets, killing four and injuring one. He had exhibited behavioral changes as far back as ve years,
and as recently as the day prior to the attack. In 2014, his family noted that he became depressed and started using
drugs, aer which he became paranoid, violent, and lost his job in construction. Over time, he stopped living with his
mother and began staying in shelters and living on the streets. More recently, not only did his family note that he was
further deteriorating mentally, but neighbors for whom he performed odd jobs also noted some changes. e attacker
spoke to them about feeling stressed, and then suddenly stopped coming by. e day before the attack, a neighbor who
saw him lying in a stairwell of his mother’s building noted that he looked more withdrawn than usual, just laid there,
and avoided eye contact. She would later state that he just seemed dierent, not normal, and that when she saw his
eyes, it seemed like he was not there.
Although a behavioral change does not indicate someone is planning a mass attack, it does provide a window of
opportunity to engage with that individual, gather insight into why that behavior change occurred, and identify
appropriate responses.
Social Media Use
Half (n = 18, 49%) of the attackers had at
least one identied social media account
where they posted, shared, or liked
content, including accounts on Facebook,
Twitter, Instagram, LinkedIn, Snapchat,
MySpace, YouTube, and SoundCloud.
e volume of activity seen on social
media ranged from low to high among
the attackers. Some of the online content
included typical behavior, such as
sharing photos of family. Other content
included information about suicidal
ideations, drug use, violence, hate toward
a particular ethnic group, and previous
mass shootings.
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SOCIAL ISOLATION
Nearly one-third (n = 11, 30%) of the attackers self-identied or
were described by others as withdrawn, loners, or anti-social.
For some, these behaviors were noted by those who knew them
from an early age. For others, the behaviors were observed during
their school or college years, at their places of work, or in their
neighborhoods. Attackers were classied as socially isolated for
behaviors that went beyond simply not having many friends or
choosing not to participate in various social activities. Rather, they
were considered socially isolated for a range of behaviors, from
consistently showing a clear discomfort around others in dierent
contexts or ignoring social cues, to more overt behaviors like
actively or physically avoiding contact with others. Many attackers
studied by the Secret Service over the previous three years have
displayed these types of socially isolating behaviors.
ISOLATING BEHAVIORS: On May 31, 2019, a 40-year-old male opened re at a city municipal center, killing
12 and injuring 5, before he was killed by police. e attacker had given his two-week notice earlier in the day and
was reportedly distressed in the days leading up to the attack. ough the attacker appeared to have been social in
his youth, he was more isolated in the last decade of his life. At work, he would keep his oce door closed and was
described as private, shy, and reserved. One co-worker noted that he was selective about with whom he would speak.
He rarely attended work events, and when he did, he kept to himself. Estranged from his biological father’s side of the
family for many years, relatives noted that he could be “paranoid, introverted, and uncomfortable around people.”
ough some neighbors said he seemed nice, others noted he never smiled at them and they rarely saw him outside of
his residence.
PHYSICAL AVOIDANCE:
On July 28, 2019, a 19-year-old male opened re at a local community festival, killing 3
and injuring 17 others. Less than one minute aer he began ring, police confronted him and shot him multiple times
before he fatally shot himself in the head. Students and teachers from his high school, who were interviewed aer the
attack, noted that he did not make much of an impression at the school. ree months prior to the attack, he moved
to a small town and had very little contact with others. At one point, he moved into an unfurnished triplex with few
belongings and paid three months’ rent in cash. Speaking of his tenants, the property manager said, “I don’t think
anybody knows anybody [at this property] because they’re there to get away from everybody else.” Residents would
later report that they noticed his presence as a new person in the sparsely populated area, but they seldom saw him.
One neighbor said he saw the attacker walk to the mailbox and occasionally leave his apartment, but never spoke to
him or even heard his voice.
Social Isolation
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ELICITED CONCERN
Two-thirds of the attackers (n = 24, 65%) in this report
exhibited behaviors that elicited concern in other people.
ose who were concerned had various degrees of
association with the attackers, from those with whom the
attacker was close (e.g., family and friends) to those with
whom they had infrequent or peripheral contact. Most
oen, the attackers elicited concern from multiple people
in their lives. For over half of the attackers (n = 21, 57%),
the behaviors they engaged in concerned others to the
point that the observer feared for the safety of themselves
or others.
e behaviors that elicited concern in others varied
across the attackers. ey included:
• Expressions of homicidal/suicidal ideations
• Domestic violence
• Social media posts with concerning content
• reatening statements toward others
• Weapons purchases
• Harassing or stalking behaviors
• Bizarre/incoherent behavior
• Non-compliance with mental health medication
• Signs of depression
• Increased isolation
• Acts of self-harm
• Poor school attendance
• No longer paying bills
Concerned bystanders oered a variety of responses to these behaviors, from avoiding the attacker to voicing their concern
to others. Some bystanders engaged in more overt eorts to seek help, like transporting the attacker for a mental health
evaluation. Other responses included:
• Romantic partners ling for protective orders, getting a divorce, or otherwise ending the relationship;
• Parents seeking therapy for the attacker, reminding them to take prescribed mental health treatment, requiring them
to move out of the house, or calling law enforcement;
• Colleagues avoiding the attacker, ring them, or confronting them with their concerns;
• Fellow students telling school sta about their concerns, reporting the behavior to a designated central reporting
mechanism, or speaking with the attacker about their concerns;
• School personnel notifying parents about their concern or expelling the attacker from school.
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CONCLUSION
Tragically, many communities across the country were impacted by mass violence in 2019. All available data indicates
that these acts of violence are rarely spontaneous and are almost always preceded by warning signs, thereby oering
opportunities for prevention. e U.S. Secret Service stands ready to support our community partners in this vital public
safety mission, with the same eort we dedicate to our no-fail mission of protecting the nation’s highest elected ocials.
ese tragedies are preventable if the appropriate community systems are in place. is report supports the Secret
Service’s long-standing recommendation that multidisciplinary threat assessment programs should be part of any violence
prevention plan. A threat assessment is designed to identify and intervene with individuals who pose a risk of engaging in
targeted violence, regardless of motive, target, or weapon used.
is approach requires an enhanced understanding and awareness of the types of behaviors that tend to precede acts
of violence. NTAC’s research into mass attacks has demonstrated that no two attacks or attackers are exactly alike. For
example, all of the mass attacks that occurred in 2017 or 2018 were carried out by lone attackers, while this year’s analysis
included three attacks that were carried out by pairs of attackers. However, NTAC continues to identify commonalities
that frequently appear in attackers’ backgrounds and provide public safety ocials an opportunity for intervention.
For example, this study identied a signicant relationship between substance abuse and domestic violence in the
histories of the 37 attackers, two areas deserving of enhanced community resources. While a history of drug abuse or
domestic violence does not precede every mass attack, the frequency with which these factors are observed highlights the
importance of providing appropriate interventions in these situations.
e ndings from this report reinforced similar ndings from previous NTAC studies on mass attacks, including the
prevalence of ideological beliefs, grievance-based motives, and a history of violence, among others factors. is year’s study
expands on these ndings by examining additional factors, such as home life and current living situations, behavioral
changes, social isolation, employment status, and online activity. During the analysis of these 34 attacks from 2019,
NTAC researchers identied key ndings that should immediately inuence the violence prevention strategies used by
communities across the United States. ese ndings include:
• e attacks impacted a variety of locations, including businesses/workplaces, schools, houses of worship, military
bases, open spaces, residential complexes, and transportation.
• Most of the attackers used rearms, and many of those rearms were possessed illegally at the time of the attack.
• Many attackers had experienced negative home life factors, unemployment, substance use, mental health symptoms,
• or recent stressful events.
• Attackers oen had a history of prior criminal charges or arrests and domestic violence.
• Most of the attackers had exhibited behavior that elicited concern in family members, friends, neighbors, classmates,
co-workers, and others, and in many cases, those individuals feared for the safety of themselves or others.
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In order to address each of these key ndings, the U.S. Secret Service oers the following for consideration:
ESTABLISH THREAT ASSESSMENT PROGRAMS: e attacks examined in this report aected the places where we work,
learn, and otherwise live our daily lives. reat assessment teams can be established in many of these environments, with
the goal of identifying and intervening with individuals who may pose a risk of harm to themselves or others. Police
departments, workplaces, military installations, government agencies, universities, and K-12 schools can implement these
types of programs as part of an overall violence prevention strategy.
For the past 20 years, the U.S. Secret Service has provided guidance on the establishment of threat assessment programs
to law enforcement, schools, government agencies, and others, beginning with the publication of the agency’s rst
threat assessment guide, Protective Intelligence & reat Assessment Investigations: A Guide for State and Local Law
Enforcement Ocials. e North Carolina State Bureau of Investigation’s Behavioral reat Assessment (BeTA) Unit
18
is an
example of a state law enforcement agency using a proactive approach to prevent violence in the community, by intervening
with those individuals identied as having the means and motive to perpetrate an act of targeted violence. Similarly, the U.S.
Department of Veterans Aairs operates a Workplace Violence Prevention Program (WVPP),
19
which incorporates threat
assessment and management practices as part of a robust workplace safety plan.
More recently, the Secret Service published updated guidance for K-12 violence prevention programs, titled Enhancing
School Safety Using a reat Assessment Model: An Operational Guide for Preventing Targeted School Violence. ese
types of programs operate in many schools across the country and regularly facilitate students receiving counseling services
or other interventions when they are in crisis.
ENFORCE EXISTING FIREARMS LAWS: e majority of mass attacks in the United States are carried out using rearms. In
each of the past three years, the Secret Service found that at least 40% of these shootings in public spaces involved a rearm
that was illegally possessed at the time. Federal law establishes several prohibiting factors that make it unlawful for an
individual to purchase or possess a rearm. ese factors include a prior felony conviction, a dishonorable discharge from
the military, and being the subject of a current restraining order. Other noteworthy prohibiting factors include illegal drug
use within the past year and any prior conviction for a crime of domestic violence. All law enforcement and other public
safety ocials must be aware of these longstanding federal restrictions, as well as any additional state or local restrictions,
and take steps to ensure these laws are enforced.
PROVIDE CRISIS INTERVENTION, DRUG TREATMENT, AND MENTAL HEALTH TREATMENT: Many attacks in 2019 were
perpetrated by individuals who had experienced unemployment, substance use, mental health symptoms, and/or recent
stressors. While there is no sure way to predict human behavior or attribute violence to a single cause, early intervention
is a demonstrated best practice for preventing unwanted behavior. Providing resources to address factors like drug abuse,
mental illness, unemployment, and other personal crises is of utmost importance at the community level. Workplaces,
schools, and communities at large should provide support for individuals experiencing these types of distress. For example,
many universities operate behavioral intervention teams to promote well-being within the campus community. ese cross-
campus groups collaboratively facilitate access to mental health and substance abuse treatment, nancial and academic
supports, and other necessary resources for members of the campus community. Early intervention not only improves the
outlook for the individual in need, but also reduces the likelihood of further escalation or future conicts.
United States Secret Service
NATIONAL THREAT ASSESSMENT CENTER
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 27
“reat assessment” refers to a proactive approach to violence prevention. It is an investigative model originally
developed by the U.S. Secret Service to prevent assassinations, but has since been adapted to prevent all forms
of targeted violence, regardless of motivation. is includes K-12 school shootings and acts of workplace violence.
When implemented eectively, a threat assessment generally involves three key components:
Identify
Assess
Manage
U.S. Secret Service research indicates that the majority of perpetrators of targeted violence elicit
concern in others prior to the attack. We rely on the people who observe such concerns to identify the individual
to law enforcement or to someone else with a public safety responsibility. In educational settings or workplaces,
concerns may be reported to a multidisciplinary threat assessment team that works in conjunction with law
enforcement when needed. e responsible public safety entity is then tasked to assess the situation to determine
how it can manage any risk of violence posed by the individual. With a focus on early intervention, this systematic
approach is an important component of any safety plan. It allows communities to respond appropriately to a
broad range of situations, from individuals who are displaying a low-level concerning behavior to those who
may pose an immediate and imminent risk of violence.
RECOGNIZE THE RISK OF CRIME AND VIOLENCE: Law enforcement is a necessary component of any threat assessment
involving an imminent safety risk or criminal behavior. While many situations may allow for the proactive management
of low-level concerning behaviors without involving law enforcement, violence and other criminality must not be ignored.
Half of the attackers in this report had a criminal history, with nearly one-quarter facing prior charges for violent crimes.
What’s more, nearly half of the attackers had a history of violence toward others, but only some of those individuals faced
criminal charges or meaningful consequences for the behavior. is included 13 attackers who committed prior acts of
domestic violence, only 7 of whom were arrested for those acts. Criminal and violent behavior should rapidly escalate the
assessment of risk an individual poses.
ENCOURAGE REPORTING OF CONCERNING BEHAVIOR: Most of the attackers in this study elicited concern in others, and
in many of those cases, the attacker caused people to feel concerned for the safety of themselves or others. ese warning
signs must be shared with those who have the capacity or authority to act. When concerns about safety are reported, a
multidisciplinary response must be brought forth to ensure the safety of the individuals of concern and the people in their
community. Workplaces, schools, and public services can establish central reporting mechanisms where the public can
report their concerns. Some of the most eective versions of reporting programs have been developed for K-12 schools.
ese programs encourage students, parents, and teachers to not only report concerns about safety, but about any concern
regarding the well-being of students. is reporting allows for the identication of students in need and allows the school
to facilitate interventions where needed. Programs like this have been established in workplaces and on college campuses,
as well. In some places, state or local governments have developed reporting programs for use by the general public.
e U.S. Secret Service’s NTAC will continue to build upon our existing body of research surrounding targeted violence
and will provide training and consultation to our public safety partners on how such violence can be prevented. With the
appropriate information, resources, and policies, we can prevent these tragedies and the loss of life that follows.
United States Secret Service
NATIONAL THREAT ASSESSMENT CENTER
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 28
019 FINDINGS Business/Service Open S paces
Attackers
17 persons, 15 attacks 11 persons, 11 attacks
Age
range of 20-65; avg. 36 range of 19-36; avg. 29
Harm
1/2 of those
harmed were killed
3/4 of those
harmed, survived
Mental health
Over 1/4 had symptoms Over 1/2 had symptoms
Intended targets
1/3 had intended targets Only 1 had an intended target
Grievances
Nearly half had grievance
as part of the motive
Only 1 had grievance
as part of the motive
SUMMARY AND TABLES
Most Prevalent Locations in 2019
In 2019, 24 attacks (71%) took place at business/service-related sites and/or open spaces.*
Behavioral Overview
e majority of attackers had:
Signicant stressors within ve years, and over
half had nancial instability
Most attackers had:
Prior threatening or concerning communications
Elicited concern from others
About half had histories of:
Substance use or abuse
Criminal charges
Violence toward others (including domestic violence)
Just under half of the attackers had:
reatened someone in the past
An unstable home life at the time
Exhibited changes in behavior
Some attackers:
Were known to be unemployed
Were considered isolated, withdrawn, or loners
Had experienced a triggering event
Subscribed to ideological/hateful beliefs
Had adverse childhood experiences
13
2017 2018 2019
20
15
2017 2018 2019
8
4
11
* Two attackers were in both categories.
United States Secret Service
NATIONAL THREAT ASSESSMENT CENTER
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 29
INCIDENT OVERVIEW
2017
n = 28
2018
n = 27
2019
n = 34
Weapons
20
Firearms 82% 89% 71%
Possessed illegally
21
10 of 23
rearms cases
10 of 24
rearms cases
10 of 24
rearms cases
Bladed weapons 7% — 18%
Vehicles 11% 11% 12%
Blunt objects — — 9%
Duration
Less than 5 min. 50% 63% 47%
5 – 14 min. 21% 22% 15%
15 min. or more 29% 15% 38%
Locations: 89 incidents, 95 public or semi-public sites
22
Business/services 46% 74% 44%
Services 11% 22% 18%
Restaurants/bars 7% 22% 9%
Health services 7% 15% —
Retail 11% — 12%
Manufacturing and
distribution
4% 7% 3%
Government 4% 4% 3%
Open spaces 29% 15% 32%
Education-related 14% 11% 9%
Communal space 4% — 6%
Houses of worship 7% 4% 6%
Military — — 6%
Transportation 11% — 3%
United States Secret Service
NATIONAL THREAT ASSESSMENT CENTER
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 30
GENERAL BACKGROUNDS
2017
n = 28
2018
n = 27
2019
n = 37
Sex - Male 100% 93% 92%
Age: range 15-66 15-64 16-80
average 37 37 33
Illicit drug use or substance abuse 54% 22% 46%
History of criminal charge(s) 71% 48% 51%
Non-violent 57% 37% 51%
Violent 54% 22% 22%
Overall history of violence 64% 44% 46%
History of domestic violence 32% 30% 35%
Mental health symptoms 64% 67% 46%
Known treatment or diagnosis 25% 44% 32%
Beliefs 25% 30% 24%
Fixation 39% 41% 19%
Stressors 100% 89%
23
87%
Financial instability 57% 56% 54%
Threatening or concerning
communications
86% 93% 65%
History of making threats 50% 37% 43%
Threats specic to the target 36% 22% 22%
Concerning communications 82% 85% 57%
Elicited concern 79% 78% 65%
Concern about safety 46% 70% 57%
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NATIONAL THREAT ASSESSMENT CENTER
Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 31
LIST OF INCIDENTS
1) On January 15, a male used a hammer to kill three at a
restaurant in Brooklyn, NY.
2) On January 23, a male fatally shot ve women inside a
bank in Sebring, FL.
3) On January 24, a male injured his former girlfriend and
killed two when he opened re at a bar and grill in State
College, PA.
4) On January 29, a male drove his vehicle into people at a
homeless encampment, injuring four in Modesto, CA.
5) On February 15, a male fatally shot ve and injured one
before injuring ve responding ocers at a warehouse in
Aurora, IL.
6) On February 21, a male fatally shot his girlfriend
before killing one and wounding two at a gas station in
Elizabethtown, KY.
7) On March 27, a male fatally shot one and injured two in
vehicles and on a bus, before killing another with a vehicle
in Seattle, WA.
8) On April 1, a male fatally stabbed and/or shot four
employees at a property management company in
Mandan, ND.
9) On April 23, a male used his vehicle to hit and injure eight
in a crosswalk in Sunnyvale, CA.
10) On April 27, a male fatally shot one and injured three at a
synagogue in Poway, CA.
11) On April 30, a former student fatally shot two and injured
four in a classroom at a university campus in Charlotte,
NC.
12) On May 7, two students fatally shot one classmate and
injured six at their high school in Highlands Ranch, CO.
13) On May 29, a male fatally shot two and injured one, before
injuring a responding ocer, at a plumbing company in
Cleveland, TX.
14) On May 31, a male fatally shot 12 and injured 5 at his
oce building in Virginia Beach, VA.
15) On June 17, a male drove onto sidewalks and into a
building, injuring two and killing a woman, her son, and
unborn child in Jeerson City, TN.
16) On July 4, a male injured three using a knife at a plasma
center in Petersburg, VA.
17) On July 9, a male injured three using a 3.5-inch folding knife
on the street in Seattle, WA.
18) On July 28, a male fatally shot 3 and injured 17 at a public
agricultural festival in Gilroy, CA.
19) On August 3, a male fatally shot 23 and injured 22 at a
superstore in El Paso, TX.
20) On August 4, a male fatally shot 9 and injured 20 in a bar
district in Dayton, OH.
21) On August 31, a male fatally shot 7 and injured 25 as he drove
through Midland and Odessa, TX.
22) On September 28, a male injured ve, stabbing three
and bludgeoning two, at an outdoor shopping center in
Cockeysville, MD.
23) On October 3, a male fatally shot one and injured two at a
cemetery in Wausau, WI.
24) On October 3, a male fatally shot one and injured two in the
lobby of a senior-living apartment complex in Vancouver, WA.
25) On October 5, a male used a 15 lb. piece of metal to kill four
and injure one in New York City, NY.
26) On October 6, two males opened re in a bar, killing four and
injuring ve in Kansas City, KS.
27) On October 21, a male stabbed and injured three on a bus on
the Pennsylvania Turnpike.
28) On October 21, a male shot and injured four in two locations
in Sumter, SC.
29) On November 14, a student fatally shot two classmates and
injured three at his high school in Santa Clarita, CA.
30) On December 4, a male fatally shot one and injured two at a
naval base in Honolulu, HI.
31) On December 6, a male fatally shot three and injured eight at
a naval base in Pensacola, FL.
32) On December 10, a male and a female fatally shot three and
injured three at a kosher market in Jersey City, NJ.
33) On December 19, a male resident opened re in the
administrative oce of his apartment complex, killing one
and injuring two in Westerly, RI.
34) On December 28, a male used a machete to injure four
and kill one at a rabbi’s home adjacent to a synagogue in
Monsey, NY.
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Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 32
ENDNOTES
1
The incidents included in this report were identied and researched through open source reporting (e.g., media sources and publicly available law enforcement records);
therefore, it is possible that more took place than were discovered at the time of this writing. Further, the limitations of open source information should be considered when
reviewing the ndings contained in this report. Since information for a few of the attackers was limited, it is likely that a larger number than reported here may have displayed the
behaviors, symptoms, and other background elements.
2
This report was prepared for educational and research purposes. The background and behaviors reported herein are of those individuals who: 1) were arrested for the act; 2) died
at the scene; or 3) died immediately following the attack. Actions attributed to individuals who have been arrested, indicted, or charged in these incidents are merely allegations,
and all are presumed innocent until proven guilty beyond a reasonable doubt in a court of law.
3
When identifying cases for inclusion in this report, there were several attacks in public spaces worth noting that did not meet one or more of the criteria, or had insucient
information to conrm their inclusion. These attacks included: 1) a man who opened re at a moving company, injuring ve (four from gunre) – there was insucient
information to conrm that this was not a spontaneous altercation or part of a criminal act for monetary gain; 2) a man who opened re in a bookstore, causing minor injuries
to several patrons – the weapon used was a pellet gun; 3) a man who red into a crowd at a concert, injuring six – there was insucient information to conrm it was not a
spontaneous altercation or gang-related; and 4) a recently suspended employee opened re at a large retail store, injuring two employees and a responding police ocer –
though this was a targeted attack at a public space, it did not meet the denition of a mass attack for the purpose of this report, which excludes injuries to rst responders
occurring after the initiation of the attack.
4
In one incident, the attacker used a long gun to inict harm on others and used a handgun to kill himself. As the handgun was not used to harm others, it was not included
amongst the handguns noted here. However, it was counted in the total number of weapons brought to the site.
5
Though illegal drug use within the previous year is one of the disqualifying factors for possessing a rearm under federal law, it was not included as a prohibiting factor here, as
information was not always available to conrm active use within one year of the incident prior to its initiation. In at least one case beyond those counted here, an attacker had
illegal drugs in his system at the time of the shooting, thereby rendering his possession of the rearm illegal under federal law.
6
One additional attacker used a switchblade, which was illegally possessed as state law prohibits such knives.
7
For 2017–19, 89 attacks took place at 95 public sites as several of the attackers caused harm at more than one distinct location. For the 2019 attack that took place at a shopping
center, for the purposes of this report, the site was considered a business.
8
The percentages for the locations in this section were calculated based on the 34 incidents.
9
Attacks at residential locations were only included if the attack took place in a communal area of a residential complex (e.g., an apartment building lobby).
10
The number of resolutions described in this section equals 35 as for one of the incidents with two attackers, one of them was stopped by a bystander and the other by private
security. The percentages presented were calculated using the 34 attacks.
11
For one attack, it was not clear in open sources if the attacker ended the attack on his own or was stopped by a bystander.
12
Analysis to evaluate whether the relationship between domestic violence and substance abuse was statistically signicant involved a two-sided Fisher’s exact test. Histories
of domestic violence and substance abuse were both present in over a quarter of the attackers, while half had no history of either. The relationship was statistically signicant
(p = .002).
13
Centers for Disease Control and Prevention. (2018, January 26). Learn about mental health. https://www.cdc.gov/mentalhealth/learn/index.htm.
14
The lower percentage of any mental health symptom may be attributed to the lack of substantive information available in open source of some of the incidents.
15
Perälä, J., Suvisaari, J., Saarni, S. I., Kuoppasalmi, K., Isometsä, E., Pirkola, S., Partonen, T., Tuulio-Henriksson, A., Hintikka, J., Kieseppä, T., Härkänen, T., Koskinen, S., & Lönnqvist, J.
(2007). Lifetime prevalence of psychotic and bipolar I disorders in a general population. Archives of General Psychiatry, 64(1), 19-28. doi:10.1001/archpsyc.64.1.19.
16
Paranoia may also be indicative of other types of conditions such as personality disorders, mood disorders (e.g., bipolar disorder), an adverse eect of substance use/abuse, or
even a symptom of an underlying medical condition. For the purposes of this study, it is captured within psychotic symptoms due to the context of the subject’s life and the
information available in open sources.
17
The National Threat Assessment Center. (2019). Protecting America’s Schools: A U.S. Secret Service Analysis of Targeted School Violence. U.S. Secret Service, Department of Homeland
Security. https://www.secretservice.gov/data/protection/ntac/Protecting_Americas_Schools.pdf.
18
See North Carolina State Bureau of Investigations. Behavioral Threat Assessment (BeTA) Unit. Available from https://ncsbi.gov/BeTA.
19
See U.S. Department of Veterans Aairs operates a Workplace Violence Prevention Program (WVPP).
Available from https://www.publichealth.va.gov/about/occhealth/violence-prevention.asp.
20
Percentages for 2019 exceed 100 as three of the attacks involved a combination of weapons, including one involving a rearm and a knife, another committed with a rearm and
a vehicle, and another in which a knife and glass bottles were used to cause harm.
21
Though illegal drug use within the previous year is one of the disqualifying factors for possessing a rearm under federal law, it was not considered in this review as information
was not always available to conrm active use in that timeframe prior to the initiation of the attack.
22
The 95 types of locations include the general category of business/services, not the individual sub-sectors.
23
This percentage, which changed from 85% to 89%, was updated to reect additional information identied since Mass Attacks in Public Spaces - 2018 was released.
United States Secret Service
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Mass Attacks in Public Spaces - 2019 LIMITED TO OPEN SOURCE INFORMATION 33
PHOTOGRAPHS Cover: iStock.com/ThamKC; Page 6: iStock.com/Michael Wels; Page 8: iStock.com/Kwangmoozaa; Page 10: iStock.com/LukaTDB;
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PHOTOGRAPHS Cover: iStock.com/ThamKC; Page 6: iStock.com/Michael Wels; Page 8: iStock.com/Kwangmoozaa; Page 10: iStock.com/LukaTDB;
Page 12: iStock.com/RomoloTavani; Page19: iStock.com/MachineHeadz; Page 26: iStock.com/Michal Oska; Page 34: iStock.com/deberarr
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Mass Attacks in Public Spaces - 2019
