In the 11 months since 17 teachers and students were killed at Marjory Stoneman Douglas High School in Parkland, Florida, campuses across the country have started spending big on surveillance technology. The Lockport, New York, school district spent $1.4 million in state funds on a facial-recognition system. Schools in Michigan, Massachusetts, and Los Angeles have adopted artificial-intelligence software--prone to false positives--that scans students' Facebook and Twitter accounts for signs that they might become a shooter. In New Mexico, students as young as 6 are under acoustic surveillance, thanks to a gunshot-detection program originally developed for use by the military to track enemy snipers. Earlier this month, the Marjory Stoneman Douglas High School Public Safety Commission released its report on the safety and security failures that contributed to fatalities during last year's shooting.

In this July 10, 2018 photo, a camera with facial recognition capabilities hangs from a wall while being installed at Lockport High School in Lockport, N.Y. The surveillance system that has kept watch on students entering Lockport schools for over a decade is getting a novel upgrade. Facial recognition technology soon will check each face against a database of expelled students, sex offenders and other possible troublemakers. It could be the start of a trend as more schools fearful of shootings consider adopting the technology, which has been gaining ground on city streets and in some businesses and government agencies. Just last week, Seattle-based digital software company RealNetworks began offering a free version of its facial recognition system to schools nationwide.