Frequent lockdowns may have contributed to Uvalde tragedy

Teachers and students at Robb Elementary School knew the safety protocols when an 18-year-old with an AR-15 style rifle entered the building in May. Dozens of times in the previous four months alone, the campus had gone into lockdown or issued security alerts.

Not because of active shooter scares — because of nearby, often high-speed pursuits of migrants coming from the U.S.-Mexico border.

An entire generation of students in America has grown up simulating lockdowns for active shooters, or worse, experiencing the real thing. But in South Texas, another unique kind of classroom lockdown occurs along the state's 1,200-mile southern border: hunkering down because Border Patrol agents or state police are chasing migrants who are trying to evade apprehension.