The investigation continues into yesterday's horrific mass shooting at a high school in Parkland, Florida.
Law enforcement officials say a former student suspected of killing at least 17 people and injuring more than a dozen others had posted some ``very, very disturbing'' material on social media before the deadly shooting rampage.
Broward County Sheriff Scott Israel says the 19-year-old suspect in custody, Nikolas Cruz, had been expelled from the school last year because of unspecified disciplinary reasons.
Cruz is accused of entering the school and opening fire with a semiautomatic weapon.
President Trump tweeted his condolences and said no one should feel unsafe at an American school.
It's a far cry from the emotional national address Barack Obama gave after the 2012 Sandy Hook massacre in Newtown, Connecticut.