In 2009 he published his research on ten school shooters based on the analysis of the Columbine High School massacre, the Virginia Tech shooting, the Red Lake shootings, the Thurston High School shooting, the Parker Middle School dance shooting, the Westside Middle School shootings, the Heath High School shooting and the Bethel Regional High School shooting. Langman's book "Why Kids Kill: Inside the Minds of School Shooters" has been translated into German, Finnish, and Dutch. When the book had been found in Munich shooter’s home as well as in the Arapahoe High School shooter’s home, a discourse began regarding whether the shooters had used the book as inspiration or for looking for a role model, someone to emulate.