Book

"a multifaceted study that is alternately horrifying, depressing, and even hopeful” –Kirkus Reviews
"a sensitive and knowledgeable treatment of one of America’s most vexing social problems.” –Publishers Weekly


Winner of the 2022 Minnesota Book Award

“This is a thorough, groundbreaking work. … A gripping book that will captivate anyone" –Library Journal (starred review)
“One of the most comprehensive studies of the subject” –Wall Street Journal

Peer-Reviewed

Taylor & Francis


Exploring the overlap: Suicidal thoughts and homicidal acts among incarcerated offenders

Peterson, J., & Densley, J. (in press). Deviant Behavior.
https://doi.org/10.1080/01639625.2024.2443778

Taylor & Francis


Murder in a time of crisis: a qualitative exploration of the 2020 homicide spike through offender interviews

Densley, J., & Peterson, J. (in press). Journal of Crime and Justice.
https://doi.org/10.1080/0735648X.2024.2426502

AJPM


Factors associated with secure firearm storage among U.S. gun owners

Densley, J., Pyrooz, D., & Peterson, J. (2025). American Journal of Preventive Medicine, 69(1), 107635.
https://doi.org/10.1016/j.amepre.2025.04.005

Nature


Mental health consequences of exposure to mass and non-mass shootings in a national sample of U.S. adults

Peterson, J., Densley, J., & Pyrooz, D. (2025). Nature Mental Health.
https://doi.org/10.1038/s44220-025-00413-7

JAMA Network Open


Direct exposure to mass shootings among US adults

Pyrooz, D., Densley, J., & Peterson, J. (2025). JAMA Network Open, 8(3), e250283.
https://doi.org/10.1001/jamanetworkopen.2025.0283

Annual Reviews


Epidemiology of mass shootings in the United States

Peterson, J., Densley, J., Hauf, M., & Moldenhauer, J. (2024). Annual Review of Clinical Psychology, 20, 125–148.
https://doi.org/10.1146/annurev-clinpsy-081122-010256

APA


An exploration of K–12 school shooting threats in the United States

Peterson, J., Densley, J., Riedman, D., Spaulding, J., & Malicky, H. (2024). Journal of Threat Assessment and Management, 11(2), 106–120.
https://doi.org/10.1037/tam0000215

SAGE


How mass public shooters use social media: Exploring themes and future directions

Peterson, J., Densley, J., Spaulding, J., & Higgins, S. (2023). Social Media + Society, 9(1).
https://doi.org/10.1177/20563051231155101

Elsevier


US mass public shootings since Columbine: victims per incident by race and ethnicity of the perpetrator

Jewett, P., Gangnon, R., Borowsky, I., Peterson, J., Areba, E., Kiragu, A., & Densley, J. (2022). Preventive Medicine, 162, 107176.
https://doi.org/10.1016/j.ypmed.2022.107176

APA


Psychosis and mass shootings: A systematic examination using publicly available data

Peterson, J., Densley, J., Knapp, K., Higgins, S., & Jensen, A. (2022). Psychology, Public Policy, and Law, 28(2), 280–291.
https://doi.org/10.1037/law0000314

JAMA Network Open


Communication of intent to do harm preceding mass public shootings in the United States, 1966–2019

Peterson, J., Erickson, G., Knapp, K., & Densley, J. (2021). JAMA Network Open, 4(11), e2133073.
https://doi.org/10.1001/jamanetworkopen.2021.33073

JAMA Network Open


Presence of armed school officials and fatal and nonfatal gunshot injuries during mass school shootings, United States, 1980–2019

Peterson, J., Densley, J., & Erickson, G. (2021). JAMA Network Open, 4(2), e2037394.
https://doi.org/10.1001/jamanetworkopen.2020.37394

SAGE


Evaluation of “the R-Model” crisis intervention de-escalation training for law enforcement

Peterson, J., Densley, J., & Erickson, G. (2020). The Police Journal, 93(4), 271–289.
https://doi.org/10.1177/0032258X19864997

Taylor & Francis


Is Crisis Intervention Team (CIT) training evidence-based practice? A systematic review

Peterson, J., & Densley, J. (2018). Journal of Crime and Justice, 41(5), 521–534.
https://doi.org/10.1080/0735648X.2018.1484303

Elsevier


Group aggression

Densley, J., & Peterson, J. (2018). Current Opinion in Psychology, 19, 43–48.
https://doi.org/10.1016/j.copsyc.2017.03.031

Elsevier


Cyber violence: what do we know and where do we go from here?

Peterson, J., & Densley, J. (2017). Aggression and Violent Behavior, 34, 193–200.
https://doi.org/10.1016/j.avb.2017.01.012

Essays and Op-Eds