After Florida massacre, Trump urges students to ‘always report’ classmates for ‘erratic behavior’

President Donald Trump on Thursday responded to the latest school shooting by encouraging high schoolers to report classmates to authorities if they are seen exhibiting "erratic behavior."

"So many signs that the Florida shooter was mentally disturbed, even expelled from school for bad and erratic behavior," the president wrote. "Neighbors and classmates knew he was a big problem. Must always report such instances to authorities, again and again!"

17 people were killed in a mass shooting at Parkland High School in Florida on Thursday. The suspect in the shooting, 19-year-old Nikolas Cruz, allegedly conducted the massacre using an AR-15-style rifle that he was able to purchase legally.