Warning Signs: Identifying School Shooters Before They Strike

How do we prevent the next school shooting? By knowing the warning signs.

Dr. Langman’s timely book presents practical, research-based guidance on anticipating and preventing mass attacks. Warning Signs is for all members of a school community, including school personnel, mental health professionals, law enforcement officers, parents, and students. Drawing on lessons learned from dozens of thwarted plots and deadly attacks, Warning Signs provides the insight necessary to keep schools safe.

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Praise for Warning Signs

“All educators who work with students from elementary school to college age will find tools in this book to recognize warning signs, encourage proper threat assessment, and ultimately avert a tragedy. Dr. Langman’s research and work have saved lives. I know. Mine is one of them.

Molly Bradley Hudgens, Congressional Medal of Honor Citizen Honors Recipient; author of Saving Sycamore: The School Shooting that Never Happened

I wish I did not know Peter Langman. I wish his work did not matter to me, or any of us for that matter. But it does. My daughter Jaime was murdered in the Parkland school shooting. In hindsight, what happened to my daughter was preventable. This important book will take readers through identification of potential attackers and how to take action before the next mass shooting happens. For the safety of those you love, I hope you take the time to read this book.

Fred Guttenberg, gun safety activist; author of Find the Helpers

“To say that Warning Signs is a must-read doesn’t go far enough. This book should be required reading for every educator, school safety professional, and law enforcement officer in America. At a time in our history when we are faced with increased violence in our schools and communities, Dr. Langman provides a critical understanding of what we are facing and what we can do to make a difference. This book should be part of every school district’s threat management program.”

John McDonald, Executive Director, Department of School Safety, Jefferson County Public Schools

“No one has devoted more time and energy to understanding school shooters, and how to stop them, than Dr. Peter Langman.”

John Woodrow Cox, Pulitzer Prize finalist; author of Children Under Fire: An American Crisis

Warning Signs is a game-changer for educators, school staff, and community members who seek a better understanding of their role in preventing school violence.”

Michele Gay, Co-founder of Safe and Sound Schools; mother of Josephine Grace, killed at Sandy Hook

Warning Signs is essential reading for school safety professionals.”

— Mo Canady, Executive Director, National Association of School Resource Officers (NASRO)

“This book is a valuable tool for understanding how to identify individuals at risk for targeted school violence. A great read for anyone working in schools and those serving on threat assessment teams!”

— Melissa Reeves, Ph.D., Past President, National Association of School Psychologists; author of Behavioral Threat Assessment and Management for K-12 Schools

“The reality of this book and the stories of these terrible tragedies is that they were all preventable. This is a must-read for anyone responsible for building safer schools.”

— Susan Payne, Founder of Safe2Tell; Research Associate, The Center for the Study and Prevention of Violence, Colorado University

“Dr. Langman's book is like a compass for navigating the complexities of preventing the next school attack. The lessons contained in this book are a substantial contribution toward improving the safety of our nation’s schools. I wish these lessons had been learned in time to save my daughter Alaina.”

— Ryan Petty, Commissioner, Marjory Stoneman Douglas Public Safety Commission; Founder, WalkUp Foundation; Member, Florida Board of Education

“Dr. Langman’s comprehensive analysis of school shooters provides the information we need to prevent future school attacks.”

— Frank Straub, Ph.D., Director, National Police Foundation’s Averted School Violence Project

“A must-read for the school violence prevention stakeholder, Warning Signs is a valuable contribution to the field of school safety that can and will help prevent future tragedies.”

— Michael Dorn, Executive Director, Safe Havens International, co-author of Extreme Violence: Understanding and Protecting People from Hate Crimes, Active Assailants, and Terrorist Attacks

“If you want to understand the mindset and motivation of students who attacked their school, there is no better resource than this book. Most importantly, Dr. Langman also outlines how behavioral threat assessment and intervention can prevent more shootings.”

— Dewey Cornell, Ph.D., author of Comprehensive School Threat Assessment Guidelines: Intervention and Support to Prevent Violence

“This book helps the reader recognize concerning behavior, be prepared to report it, and be part of the school safety team in their community. As Dr. Langman reminds us, when it come to school safety, we’re all on duty.”

— Tony Montalto, President, Stand with Parkland, the National Association of Families for Safe Schools

“Given his decades of experience researching and studying shootings, Langman is in a unique position to provide counselors, administrators, law enforcement professionals, and human resource professionals the knowledge they need to prevent future attacks. This is a ‘don’t miss’ book.”

Brian Van Brunt, ED.D., author of Harm to Others: The Assessment and Treatment of Dangerousness and Ending Campus Violence: New Approaches to Prevention

“Peter Langman may have more experience studying the details of school shooters’ lives than any scholar or security official working today. Every time I read Langman’s work, I learn something new about what a school shooter was thinking, writing, or saying before he attacked. By identifying patterns in their pre-attack behavior, we can increase our ability to avert these tragedies and save many innocent lives.”

— Adam Lankford, Ph.D., author of The Myth of Martyrdom: What Really Drives Suicide Bombers, Rampage Shooters, and Other Self-Destructive Killers


About This Book

1 · We’re All on Duty
2 · They’re Not Who We Think They Are: Stereotypes and FAQs
3 · Leakage: When Students Reveal Their Intentions
4 · Attack-Related Behavior: When Thinking Becomes Doing
5 · Getting Psyched: Immersion in a World of Violence
6 · Motivations and Justifications
7 · Warning Signs in Student Assignments
8 · Barriers to Action
9 · Threat Assessment 101

Appendix A: Resources
Appendix B: A Glossary of Insider References
Notes and Sources
About the Author