This article examines the 1915 double murder of Jesus Bazán and Antonio Longoria north of the Rio Grande River in Hidalgo County, Texas, and shows that this event is emblematic of the wider use of violence in subject formation and state-building projects in the Americas. This article describes a state-sanctioned period of racial terror and the culture of impunity in which state agents abused their authority and denied protection to ethnic Mexicans within their jurisdiction. This period of anti-Mexican violence continues to be memorialized a century later. Generational memories of this double murder—and the vernacular histories created by local residents in Texas—continue to challenge historical narratives that disavow generational loss and obscure roots of state violence. These histories confront historical narratives that justify the violence inherent in nation-building practices and make transparent the longer legacies of histories of border policing.