This report provides a comprehensive analysis of the demographic and contextual profile of mass shooters in the United States. The central thesis is that the profile of a mass shooter is not a singular demographic type but rather a complex, multi-factorial "syndrome" rooted in the convergence of demographic, psychological, behavioral, and societal factors. The analysis moves beyond superficial media portrayals to reveal a more nuanced and evidence-based understanding of these individuals. It emphasizes that while certain demographic characteristics are prevalent, they are not causal and only become meaningful when viewed in conjunction with a series of shared, non-demographic risk factors. The investigation highlights the critical roles of premeditation, suicidal ideation, and the presence of observable pre-attack warning signs, transforming the understanding of these events from random acts of violence to often preventable catastrophes.