Advancing Understanding, and Informing 

Prevention of Public Mass Shootings: Findings 

from NIJ Funded Studies, Part 2 

November 17, 2020 

The webinar will begin shortly. 

www.nij.gov/ojp
 

 

 

 

 

 

 

 

Presentations 

Presentation Title 

Understanding School Shootings in the U.S.A, 1990-

2016 

Deadly Mass Shootings in America: Features and 

Trends across Four Decades 

Reflections on researching the lives and crimes of 

mass shooters 

Presenter 

Steven Chermak, Ph.D., Michigan State University 

Joshua D. Freilich, Ph.D., John Jay College, CUNY 

Jillian J. Turanovic, Ph.D., Florida State University 

Travis C. Pratt, Ph.D., University of Cincinnati 

Jillian Peterson, Ph.D., Hamline University 

James Densley, Ph.D., Metropolitan State University 

Disclosure: These projects are supported by Award Numbers: 2016-CK-BX-0013, 2018-75-CX-0024, and 2018-75-CX-0023 awarded by the National Institute 

of Justice, Office of Justice Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in these 

presentations and during this webinar are those of the authors/presenters and do not necessarily reflect those of the U.S. Department of Justice. 
Thank you 

Questions and Answers 

Please submit questions to “all panelists” in the Q&A box. 

Indicate which presenter the question is for. 
 

 

 

 

 

 

Understanding School Shootings 

in the U.S.A, 1990- 2016 

Joshua D. Freilich, John Jay College of Criminal Justice, CUNY 

Steven M. Chermak, Michigan State University 

Nadine M. Connell, Griffith University 

Brent Klein, University of South Carolina 

Emily Greene-Colozzi, John Jay College of Criminal Justice,

CUNY 
Outline 

• Goals and Objectives of the Project 

• Importance of Study 

• Overview of Methodology 

• Key Findings 
 

 

 

 

 

Goals and Objectives 

• Expand knowledge & address gaps about the causes of school shootings 

• Create open source DB that includes all publically known shootings w/at least 1 injury

(1990-2016) 

• Apply criminology’s Developmental Social Control theory to better understand offenders 

• Apply criminology’s SCP to better understand events 

• Produce deliverables to aid law enforcement, school officials, policy-makers, and the social

sciences 
 

 

Importance 

• Impact of School Shootings 

• Limitations of Existing Research 

• The lack of valid large-scale data 

• The lack of detailed understanding of the school environment 

• Changes over time 

• Victim attributes 

• Measurement & reliability 

• Better data=Better understanding of the problem, opportunity to assess of impact of policy initiatives. 
 

 

Methodology: Overview 

• Quantitative Analysis 

• Open source database 

• Inclusion 

• Process 

• Assessment 

• Qualitative Analysis 

• 30 Case Studies 

• Focused on in-depth capture of life course of offenders and situational crime prevention 

related to schools 
 

 

 

 

Inclusion Criteria 

• Open sources to ID events 

• 1/1/90- 12/31/16 

• Shooting with injury/fatality on K-12 school grounds/includes outdoors; Excludes universities 

• 50 states & U.S. territories 

• At least 1 gun-shot/bullet injury or death 

• Includes rampage; work place; drugs; suicide; gangs, etc. 

• Excludes plots 
 

 

 

 

 

 

 

 

Did the incident occur 

on or after January 1, Yes 

1990? 

No 

DO NOT 

CODE No 

Did the shooting lead 

to one or more physical 

injuries and/or deaths? Yes 

Did the incident occur 

in the United States? 

Did the incident lead to 

a criminal justice 

response? 

Was a gun fired? 

Did this occur on grade 

K-12 school Grounds? 

Yes 

No 

This includes the 50 states & 

U.S. territories – DC, Puerto Rico, 

Guam, Virgin Islands. 

No Yes 

No 

No 

Yes 

This excludes: bus stops, walking 

to school, as well as pre-schools, 

colleges/universities, school board 

meetings at non-school locations, 

etc. 

This includes police responses and 

incidents in which the suspect was 

killed or escaped. 

Yes 

This includes: accidental discharges 

as well as bb/pellet guns. 

This includes: elementary, 

junior high, middle, & high 

schools of all types (i.e., 

vocational, alternative, 

career centers, etc.). 

Parking lots, extracurricular 

activities, & school buses 

are included. Anywhere on 

school grounds/property & 

on property where 

the school is in charge & 

exercises authority. 

CODE THE 

CASE! 
 

 

Identifying Cases 

• Review sources to ID relevant cases (Conducted by PIs; reviewed 35+ ) 

• Scholarly; Official; Media; Watch-Group; Web-Engines, Databases 

• Capture all known school shootings events reported in open sources 

 

 

 

 

Searching Cases 

• Collect all publically available information on each case 

– (i) 60 web-engines searches 

– (ii) Event/offender/victim search protocol & (ii) school search protocol 

• UG RAs- Extensive training: 

• Court cases (criminal & civil) 

• Department of Corrections 

• Obituaries 

• Scholarly books; other books (survivor, reporter, etc.) 

• Social media 

• Documentaries 

• Watch-groups, blogs, etc. 

• School, offender, victim photos 
 

Search Protocols (Sample) 

MASTERFILE #: MF 1 # COMMENTS 

Source: Link: 

Lexis-Nexis http://libguides.lib.msu.edu/az.php?q=nexis%20uni Y E.g. "used x and y search 

terms. # articles found" 

Proquest https://search-proquest-com.proxy2.cl.msu.edu/criminaljusticeperiodicals/index?accountid=12598 Y 

Yahoo https://www.yahoo.com/ Y 

Bing https://www.bing.com/ Y 

Google https://www.google.com/ Y 

Newsbank http://infoweb.newsbank.com.proxy1.cl.msu.edu Y 

Google Scholar https://scholar.google.com/ Y 

USA.gov https://www.usa.gov/ Y 

Google Video https://www.google.com/videohp Y 

Google News https://news.google.com/?hl=en-US&gl=US&ceid=US:en Y 

Google Images https://www.google.com/imghp?hl=en Y 

School Shooters Info https://schoolshooters.info/browse-library Y 
Table 1. Estimated Open -Source Data Coverage for Intentional U.S. School Shootings Involving Publicly Known Shooters (n 352) =

Document Type Total Mean Median St.Dev. Min Max 

Court 210 0.60 0.00 2.62 0 37 

Police 709 2.01 0.00 7.90 0 76 

Other Government 443 1.26 1.00 1.90 0 19 

Education/School 90 0.26 0.00 3.24 0 51 

News Media 26983 76.66 25.00 158.49 0 2078 

Scholarly 612 1.74 1.00 3.60 0 21 

Websites 627 1.78 1.00 31 .53 0 20 

Other 545 1.55 0.00 4.47 0 39 

Total 30148 85.65 31.50 165.23 1 2091 
 

 

 

 

 

Data Capture: Codebooks 

• Offender level DB 

• Operationalize Developmental Social Control 

• Event AND school databases 

• Operationalize Situational Crime Prevention 

• Extend ECDB 

• Case study template (Developmental Social Control & SCP) 




= =

-

 

Table 2. Characteristics of Adolescent and Adult School Shooters 

Variables Adolescent (N 250) Adult (N 102) 

Severity 

Fatal 

Non Fatal 

116/46.4% 

134/53.6% 

65/63.7% 

37/36.3% 

Number of Mass Shootings 

+3 Fatal Victims 

+4 Fatal Victims 

8/3.2% 3/2.9% 

4/1.6% 3/2.9% 

Location 

Inside School 105/42.0% 29/28.4% 

Outside School 145/58.0% 73/71.6% 

Timing 

During School Hours 108/43.2% 28/27.5% 

Before/After School Hours 142/56.8% 74/72.5% 

Student Status 

Current Student 142/56.8% N/A 
SCP/Case Study Results 

• SCP Findings 

• 5% Metal Detectors 

• 45% School Guards/Officers 

• 27% Barriers 

• 70% Limited Access 

• Criminal Opportunities 

• Easy Access to School 

• Access to Gun 

• Leakage 

• Number leaked 

• Time to Shooting 

• Response 
 

 

DEADLY MASS SHOOTINGS IN AMERICA: 

FEATURES AND TRENDS ACROSS FOUR DECADES 

Jillian J. Turanovic, Travis C. Pratt, Kristen J. Neville 
 

 

ACKNOWLEDGEMENTS 

Kristen J. Neville – Project Manager 

Dr. Travis C. Pratt – Co-Principal Investigator 

Undergraduate and graduate students at Florida State University 

This project was supported by Award No. 2018-75-CX-0024, awarded by the 

National Institute of Justice, Office of Justice Programs, U.S. Department of 

Justice. The opinions, findings, and conclusions or recommendations expressed 

in this presentation are those of the author(s) and do not necessarily reflect 

those of the Department of Justice. 
 

 

DEADLY MASS SHOOTINGS 

•Have emerged as one of the most prominent social problems in 

contemporary America 

•Such events continue to rise toward the top of U.S. citizens’ list of 

pressing concerns 

1960

197019801990200020102020

 

 

U.S. Violent Crime Rate, per 100,000 

Reality is that violent crime (and murders) were higher in 80s & 90s 

 2014 regarded as the “safest year in modern history” (Sharkey, 2018) 

Crime in the 

United States, UCR 

1960-2019. 

Source: FBI Uniform 

0 

100 

200 

300 

400 

500 

600 

700 

800 

196119621963196419651966196719681969197119721973197419751976197719781979198119821983198419851986198719881989199119921993199419951996199719981999200120022003200420052006200720082009201120122013201420152016201720182019 

Crime Reporting 

Program. 
 

 

PERCEPTIONS VS. REALITY 

100 

90 89

80 

70 

60 

50 

40 

30 

20 21 

20 20 

87 

71 71 68 70 68 

52 

41 

62 

53 

58 

67 

74 

66 

71 64

63 60 

64 

80 

54 

33 32 

28 

34 

25 26 

23 

23 

21 

23 

19 

10 

0 

% More crime in the U.S. than a year ago Violent crime rate (NCVS) (victimization per 1,000 persons) 

Sources: Bureau of Justice Statistics, National Crime Victimization Survey, 1992-2019; Gallup Annual Crime Poll, 2019. 
 

 

MASS CONFUSION 

•Have little in the way of a shared definition with respect 

to mass shootings 

•Existing databases on mass shootings paint very different 

pictures of the problem 
 

MASS CONFUSION 

Mother Jones Mass Shootings Database (1982-present): 

•Lists 10 incidents in 2019 

•Shootings where three fatalities occurred 

•Selective about what is included (no gang, felony, family, or private) 

•Unreliable data in earlier years 

•Gun Violence Archive (2013-present): 

•Lists 416 mass shootings in 2019 

•Four or more shot and/or killed in a single event, not including the 

shooter 

•Includes everything - fatal and nonfatal incidents 
 

 

MASS CONFUSION 

•FBI Active Shooter Data (2000-2019): 

•Fatal and nonfatal incidents 

•Selective about what is included 

•1 incident recorded in 2000; 28 in 2019 

•FBI Supplemental Homicide Reports (1976-2019): 

•Several crimes mischaracterized as mass killings 

•Several cases handled by federal agencies not included 

•Not all jurisdictions report; cases missing even in jurisdictions that do 
 

 

MASS CONFUSION 

•There is no comprehensive, public, centralized knowledge 

base on deadly mass shooting incidents over time 

•Difficult to determine the nature and extent of the mass 

shooting problem 
 

 

 

CURRENT PROJECT 

•Build a comprehensive database of deadly mass shootings 

•Assess the key individual, situational, and contextual 

features of all deadly mass shootings in America between 

1980-2019 

•Goal is to improve the understanding of mass shooters and 

mass shooting incidents to develop data-informed policies 
 

 

 

CURRENT PROJECT 

Four or more victims killed by firearm (not including the shooter) in 

one event, in one location 

•All deadly mass shootings, in public and private spaces 

•Capture a host of data points (100+) on each incident 

•Media reports, existing data, FBI reports, police files, court records, and 

other public records 

•Data will be made publicly available upon completion of the project 
CURRENT PROJECT 

•Three main phases: 

1. Identify all deadly mass 

shootings 

2. Gather extensive 

information on each 

incident 

3. Code each incident 

according to a host of 

characteristics 
DATA COLLECTION: LOCATING INCIDENTS 

EXISTING REPORTS LOCAL, STATE, AND NEWS MEDIA AND DATA ON MASS NATIONAL HOMICIDE REPORTS SHOOTINGS REPORTS, COURT 

RECORDS 
Incident in existing mass 

shooting dataset/report 

Official homicide 

report/court file 

News media reports 

Leads from online 

searches 

VERIFY 

INCIDENT 

(additional 

news reports, 

case files, court 

records) 

•4 or more 

shot and 

killed, not 

including the

shooter? 

•Shootings

happened on

the same 

day? 

Include 

in our 

dataset 
 

 

 

DATA THUS FAR: 1980-2019 

Verified 761 deadly mass shootings 

 Only incidents where 4+ victims were shot and killed within 24 hours 

 Did not exclude any incidents based on motive or location 

 Mass shootings in public and private spaces 

What does the overall trend in mass shootings look like over time? 
 

30 

DATA THUS FAR: 1980-2019 

DEADLY MASS SHOOTINGS (RAW COUNTS) 

0 

5 

10 

15 

20 

25 
 

30 

DATA THUS FAR: 1980-2019 

DEADLY MASS SHOOTINGS (RAW COUNTS) 

0 

5 

10 

15 

20 

25 
 

30 

DATA THUS FAR: 1980-2019 

DEADLY MASS SHOOTINGS (RAW COUNTS) 

26 27 26 

0 

5 

10 

15 

20 

25 
 

30 

DATA THUS FAR: 1980-2019 

DEADLY MASS SHOOTINGS (RAW COUNTS) 

21 

23 

26 

22 

27 

22 

24 24 

26 

24 24 

22 21 

24 

0 

5 

10 

15 

20 

25 
 

DATA THUS FAR: 1980-2019 

RATE OF MASS SHOOTINGS (PER 10 MILLION PERSONS) 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 
 

DATA THUS FAR: 1980-2019 

RATE OF MASS SHOOTINGS (PER 10 MILLION PERSONS) 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 
 1.2 

DATA THUS FAR: 1980-2019 

RATE OF MASS SHOOTINGS (PER 10 MILLION PERSONS) 

0.92 

0.99 1.03 1.04 

0 

0.2 

0.4 

0.6 

0.8 

1 
 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 
 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 

• Majority occur in private settings (69%) 

Public 

settings 

31% 

Private 

settings 

69% 

Public vs. Private Settings 
-

 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 

• Majority occur in private settings (69%) 

• Majority involve non-strangers (56%) 

Non 

strangers 

56% 

Strangers 

44% 

Strangers vs. Non-Strangers 
 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 

• Majority occur in private settings (69%) 

• Majority involve non-strangers (56%) 

• 42% involve family 

• 14% known (friends, co-workers, neighbors) 

Family 

42% 

Known 

others 

14% 

Strangers 

44% 

Strangers vs. Non-Strangers 
 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 

• Majority occur in private settings (69%) 

• Majority involve non-strangers (56%) 

• 42% involve family 

• 14% known (friends, co-workers, neighbors) 

• Romantic partner killed (27%) 

Romantic 

partner 

killed 

27% 

Other 

family 

15% 

Known 

others 

14% 

Strangers 

44% 

Strangers vs. Non-Strangers 
-

 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 

• Majority occur in private settings (69%) 

• Majority involve non-strangers (56%) 

• 42% involve family 

• 14% known (friends, co-workers, neighbors) 

• Romantic partner killed (27%) 

• One-third of shootings felony-related (33%) 

Felony 

33% 

Non 

felony 

67% 

Felony-Related Shootings 
 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 

• Majority occur in private settings (69%) 

• Majority involve non-strangers (56%) 

• 42% involve family 

• 14% known (friends, co-workers, neighbors) 

• Romantic partner killed (27%) 

• One-third of shootings felony-related (33%) 

• Female shooters rare (4%) 

Male 

shooter(s) 

only 

96% 

Female 

shooter 

4% 

Male vs. Female Shooters 
 

 

 

DATA THUS FAR: 1980- 2019 

•Verified 761 deadly mass shootings 

• Majority occur in private settings (69%) 

• Majority involve non-strangers (56%) 

• 42% involve family 

• 14% known (friends, co-workers, neighbors) 

• Romantic partner killed (27%) 

• One-third of shootings felony-related (33%) 

• Female shooters rare (4%) 

• Majority lone shooters (78%) 

One 

shooter 

78% 

Two shooters 

15% 

Three or more 

shooters 

7% 

Number of Shooters 
DATA THUS FAR: 1980-2019 

PRIMARY LOCATION OF MASS SHOOTING 

70% 66% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

7% 6% 5% 5% 3% 2% 2% 2% 2% 
 

20 

DATA THUS FAR: 1980-2019 

FAMILY-RELATED MASS SHOOTINGS (RAW COUNTS) 

0 

2 

4 

6 

8 

10 

12 

14 

16 

18 
 

20 

DATA THUS FAR: 1980-2019 

FAMILY-RELATED MASS SHOOTINGS (RAW COUNTS) 

0 

2 

4 

6 

8 

10 

12 

14 

16 

18 
 

20 

DATA THUS FAR: 1980-2019 

FAMILY-RELATED MASS SHOOTINGS (RAW COUNTS) 

12 

14 

18 

12 

0 

2 

4 

6 

8 

10 

12 

14 

16 

18 
 

DATA THUS FAR: 1980-2019 

FELONY-RELATED/OTHER MASS SHOOTINGS (RAW COUNTS) 

14 

12 

10 

8 

6 

4 

2 

0 
 

DATA THUS FAR: 1980-2019 

FELONY-RELATED/OTHER MASS SHOOTINGS (RAW COUNTS) 

14 

12 

10 

8 

6 

4 

2 

0 
 

14 

DATA THUS FAR: 1980-2019 

FELONY-RELATED/OTHER MASS SHOOTINGS (RAW COUNTS) 

13 

10 

12 

11 

12 

10 

0 

2 

4 

6 

8 

10 

12 
 

DATA THUS FAR: 1980-2019 

PUBLIC MASS SHOOTINGS (NON-FAMILY, NON-FELONY) (RAW COUNTS) 

8 

7 

6 

5 

4 

3 

2 

1 

0 
 

DATA THUS FAR: 1980-2019 

PUBLIC MASS SHOOTINGS (NON-FAMILY, NON-FELONY) (RAW COUNTS) 

8 

7 

6 

5 

4 

3 

2 

1 

0 
 

8 

DATA THUS FAR: 1980-2019 

PUBLIC MASS SHOOTINGS (NON-FAMILY, NON-FELONY) (RAW COUNTS) 

7 

6 

7 

6 6 

7 7 

6 

0 

1 

2 

3 

4 

5 

6 

7 
DATA THUS FAR: 1980-2019 

•Number of victims killed per year ranges from 46-164 

•Deadliest incidents happened in recent years 

•06/12/2016: Orlando (49) 

•10/01/2017: Las Vegas (58) 

•Are mass shootings becoming deadlier? 
 180 

DATA THUS FAR: 1980-2019 

NUMBER OF VICTIMS KILLED IN MASS SHOOTINGS (RAW COUNTS) 

0 

20 

40 

60 

80 

100 

120 

140 

160 
 180 

DATA THUS FAR: 1980-2019 

NUMBER OF VICTIMS KILLED IN MASS SHOOTINGS (RAW COUNTS) 

0 

20 

40 

60 

80 

100 

120 

140 

160 
 180 

DATA THUS FAR: 1980-2019 

NUMBER OF VICTIMS KILLED IN MASS SHOOTINGS (RAW COUNTS) 

157 164 

137 

0 

20 

40 

60 

80 

100 

120 

140 

160 
 9 

DATA THUS FAR: 1980-2019 

NUMBER OF VICTIMS KILLED IN MASS SHOOTINGS (AVERAGE PER INCIDENT) 

0 

1 

2 

3 

4 

5 

6 

7 

8 
 9 

DATA THUS FAR: 1980-2019 

NUMBER OF VICTIMS KILLED IN MASS SHOOTINGS (AVERAGE PER INCIDENT) 

0 

1 

2 

3 

4 

5 

6 

7 

8 
 9 

DATA THUS FAR: 1980-2019 

NUMBER OF VICTIMS KILLED IN MASS SHOOTINGS (AVERAGE PER INCIDENT) 

8.2 

6.5 6.4 

0 

1 

2 

3 

4 

5 

6 

7 

8 
 

 

 

NEXT STEPS 

•Currently coding each incident 

•Incident, individual, situational, and contextual characteristics 

•Data will be merged with additional state-level and census information 

•Upon completion of coding, will be able to conduct more rigorous and 

informative analyses to advance knowledge 

•The data will be made publicly available upon completion of the project 
THANK YOU! 

Jillian Turanovic 

Associate Professor 

Director, Crime Victim Research and Policy Institute 

College of Criminology and Criminal Justice 

Florida State University 

Email: jturanovic@fsu.edu 
 

Reflections on Researching the Lives and 

Crimes of Mass Shooters 

Jillian Peterson 

James Densley 

Research reported in this presentation was supported by the National Institute of Justice under award number 

2018-75-CX-0023 
 

 

 

Goal – Public Criminology 

• “...four or more victims are murdered with firearms—not 

including the offender(s)—within one event, and at least 

some of the murders occurred in a public location or 

locations in close geographical proximity ... and the 

murders are not attributable to any other underlying 

criminal activity or commonplace circumstance.” 

(Congressional Research Service, 2015) 

 

 

 

The Database: 166 Different Variables 

Primary Sources: 

• Written journals / “manifestos” / suicide notes etc. 

• Social media and blog posts 

• Audio and video recordings 

• Interview transcripts 

• Personal correspondence with perpetrators 

Community Variables: 

• Data for closest census tract year 

• U.S. Census 

• FBI UCR 

• Google Maps 

Secondary Sources (all publicly available): 

• Media (television, newspapers, magazines) 

• Documentary films 

• Biographies 

• Monographs 

• Peer-reviewed journal articles 

• Court transcripts 

• Law Enforcement records 

• Medical records 

• School records 

• Autopsy reports 


+36 Community Stakeholder Interviews 

Recruitment – publicly available data (emails), snowball sample 

• Averted shootings (n=4) • Perpetrators (n=5) • Perpetrator 

• Parents 

• Perpetrator Perspective (n=15) • School personnel 

• Spouse 

• Parents • Victim Perspective (n=5) 

• Siblings • Parents and family members 

• Extended family 

• Childhood friends • First Responders, Stakeholders (n=12) • School personnel • FBI Investigators • Social workers • Security consultants • Work colleagues/supervisors • Mental health practitioners • Shooting survivors 
2010s Average = 5.6 per year 

90s & 00s Average = 3.7 per year 

80s Average = 2.3 per year 

70s Average = 1.4 per year 
 

31.5% Mass Shootings by Location, 1966–2020 (N=168) (N=53) Note: there was an armed person on scene in 14.5% of cases 

16.7% 

(N=28) 13.7% 

(N=23) 

8.3% 7.7% 6.5% 6.5% 5.4% 

(N=14) (N=13) (N=11) (N=11) (N=9) 

3.4% 

(N=6) 

 

In Crisis 

Days 

Weeks 

Months 

Years 

Increased agitation 

Abusive behavior 

Isolation 

Losing reality 

Depressed mood 

Mood swings 

Inability Daily Task 

Paranoia 

0 

1-4 

5+ 

80.2% 

13.8% 

15.9% 

29.7% 

40.6% 

66.9% 

41.9% 

39.5% 

33.1% 

29.7% 

27.3% 

24.4% 

23.8% 

18.8% 

43.15% 

37.7% 

 

 

 

 

 

 

Role of 

Psychosis 

0. Psychotic symptoms played 

no role in the crime - 69.8% 

1. Psychotic symptoms played a 

small role in the crime - 11.0% 

2. Psychotic symptoms played a 

significant role in the crime, 

but was not the only 

motivation - 8.7% 

3. Psychotic symptoms 

completely motivated the 

crime - 10.5% 
31% of mass shooters were 

suicidal prior to their attacks, 

40% were suicidal during, 

and 59% died on the scene 
The motivations of Overall 1960-1999 2000-2015 2016-2020 

mass shooters 

(n=172) (n=77) (n=66) (n=29) 

Employment 40 (23.3%) 25 (32.5%) 12 (18.2%) 3 (10.3%) 

Interpersonal 35 (20.3%) 14 (18.2%) 15 (22.7%) 6 (20.7%) 

Psychosis 33 (19.2%) 13 (16.9%) 15 (22.7%) 5 (17.2%) 

Domestic 27 (15.7%) 11 (14.3%) 11 (16.7%) 5 (17.2%) 

Relationship 26 (15.1%) 13 (16.9%) 9 (13.6%) 4 (13.8%) 

Legal issue 22 (12.8%) 11 (14.3%) 8 (12.1%) 3 (10.3%) 

Racism 14 (9.3%) 5 (6.5%) 6 (9.1%) 5 (17.2%) 

Fame 12 (7.0%) 5 (6.5%) 3 (4.5%) 4 (13.8%) 

Religious hate 9 (5.2%) 1 (1.3%) 5 (7.5%) 3 (10.3%) 

Misogyny 7 (4.1%) 5 (6.5%) 2 (3.0%) 0 (0.0%) 
% of guns used in mass 

shootings by type 
 

Interview Data 

• Importance of case studies 

• Subjective narratives 

• Interviews on both sides 

• Trauma, coping, resilience 

• Validity check for public data 

• Warning signs and crisis points 

 

Implications 

• Firearms – closing loopholes and safe storage 

• Drills and hard security – insiders not outsiders 

• Suicide prevention and crisis intervention 

• Avoiding punishing threats 

• Reporting systems for leakage 

• Coverage in the media 

• Social media companies 
 

• jpeterson68@hamline.edu 

Thank • james.densley@metrostate.edu 

• www.theviolenceproject.org You 

• 2 articles under review 

• Book release in 2021 (interviews) 
Thank you 

Questions and Answers 

Please submit questions to “all panelists” in the Q&A box. 

Indicate which presenter the question is for.