These images are portraits of the perpetrators of the ten most fatal school shootings since the Columbine massacre in 1999 — five from the USA, two from Germany, two from Finland and one from Brazil. School shootings are a rare but repetitive phenomenon whose perpetrators share significant similarities: research shows they are motivated by individual troubles rather than political motives, and are never totally impulsive. The shooter — a young man, a student or former student of a school — slowly becomes excluded from his peers, often facing bullying.