Now they've invented something called "swatting". This is so bizarre that you need to watch the video on the linked page to get the real gist of it.
http://www.thedenverchannel.com/news/local-news/parents-warned-of-active-shooter-near-broadway-and-mineral
http://www.thedenverchannel.com/news/local-news/parents-warned-of-active-shooter-near-broadway-and-mineral