Eighteen-year-old Salvador Ramos, who was responsible for shooting and killing nearly two dozen people at Robb Elementary School in Uvalde, Texas, posted messages on social media hinting about his plans. One post read “Wait Till Tomorrow,” and “Kids Be Scared,” along with photos of two assault rifles and a high-capacity magazine. The morning of the shooting, he sent a text to someone he knew, asking, “You gonna repost my gun pics?”