| This is an OZY Special Briefing, an extension of the Presidential Daily Brief. The Special Briefing tells you what you need to know about an important issue, individual or story that is making news. Each one serves up an interesting selection of facts, opinions, images and videos in order to catch you up and vault you ahead. WHAT TO KNOW What happened? A former student killed at least 17 children and adults at a South Florida high school around dismissal time Wednesday. Suspect Nikolas Cruz, 19, reportedly pulled the fire alarm shortly before 3 p.m. at Marjory Stoneman Douglas High School in Parkland, Florida, drawing people out of the school, where he shot them with an AR-15, then moved through the halls — tossing smoke grenades and wearing a gas mask — to target those inside, who hid in bathrooms and texted their parents goodbye. He was arrested about an hour later in nearby Coral Springs. Why does it matter? This is the deadliest school shooting since the Newtown, Connecticut, massacre of 2012, and one of the top 10 deadliest mass shootings in modern U.S. history. Cruz used the same style of rifle that was used in the Newtown shooting — and those that recently stunned Las Vegas and Sutherland Springs, Texas — as some pointed out that the semi-automatic AR-15 can be bought in Florida without the waiting period or age restrictions levied on handguns. | 