On Wednesday evening, a 19-year-old gunman returning to a Florida high school where he had once been expelled opened fire with an assault rifle, killing 17 people and wounding more than a dozen others before he was arrested.
The shooting at Marjory Stoneman Douglas High School in Parkland, a placid, middle-class community about 45 miles (72 km) north of Miami, ranked as the second-deadliest act of gun violence ever on a U.S. public school campus.
It was America's 18th shooting in a school this year. It's February.
The violence follows the largest mass shooting in US history in Las Vegas, which claimed 59 lives and injured hundreds.
Since the Sandy Hook elementary school massacre in December 2012, there have been thousands mass shootings in the US.
In Decemeber after a mass shooting in a church in Texas, civil rights activist Michael Skolnik highlighted just how big a problem this is for the US and the lack of effort that has been made by politicians to introduce stricter gun laws.
One shoe bomber tried to blow up a plane and now we take off our shoes.
1520 mass shootings since Sandy Hook and Congress has done NOTHING.
The shoe bomber refers to Richard Reid, a British man who attempted to detonate a plastic explosive hidden in his shoe on a flight from Paris to Miami in December 2001.
His efforts failed but it caused US airports to introduce procedures that meant passengers have to remove their shoes when passing through security scanners.
This protocol has since been adopted by other major airports around the world.
It remains to be seen whether the US Congress will act to introduce tougher gun control after this latest shooting.
In a now infamous speech, Barack Obama asked Congress to address America's gun problem in January 2016 but the action failed to win enough support.
The Florida shooting suspect has been identified as Nikolas Cruz, who previously attended the high school and was expelled for unspecified disciplinary reasons. As a high school freshman, Cruz was part of the U.S. military-sponsored Junior Reserve Officers' Training Corp program at the school, according to Jillian Davis, 19, a recent graduate and former fellow JROTC member at Stoneman Douglas High. In an interview with Reuters, Davis recalled his "strange talking sometimes about knives and guns," adding, "no one ever took him seriously." Chad Williams, 18, a senior at Stoneman Douglas, described Cruz as "kind of an outcast" who was known for unruly behavior at school, including a penchant for pulling false fire alarms, and was "crazy about guns."
Editors note: This is an update of a story first published in November 2017