Seventeen people were killed on Wednesday at Marjory Stoneman Douglas High School in Parkland, Florida. The suspect, a 19-year-old former student, is in custody.

• It joins the list of America's deadliest mass shootings, with three of the eight deadliest in modern history coming in the last five months. There have already been several school shootings this year.
• What we know: The Broward County Sherrif's Department has identified the shooter as Nikolas Cruz, who had been expelled from school for disciplinary reasons. Police say he was armed with an AR-15 assault rifle and multiple magazines. President Trump tweeted his condolences. The White House canceled the daily press briefing and has made no further comment.

Go deeper: The deadliest mass shootings in modern U.S. history.