A gunman opened fire at a Florida high school, summoning grimly familiar scenes of fleeing students and distraught parents.

The Valentine’s Day bloodshed is the latest outbreak of gun violence that has become a regular occurrence at schools and college campuses across the United States over the past several years.

It was the 18th shooting in a U.S. school so far this year, according to gun control group Everytown for Gun Safety. That tally includes suicides and incidents when no one was injured, as well as the January shooting in which a 15-year-old gunman killed two fellow students at a Benton, Kentucky, high school.

Here is what we know about the incident in Florida so far:

What happened?

The assailant began firing at Marjory Stoneman Douglas High School toward the end of the school day, spraying bullets both inside and outside the school and sending classrooms into lockdown.

Authorities apprehended the suspected shooter off of the school’s campus and took him into a custody about an hour after the incident.

The large high school is in the city of Parkland,  about an hour north of Miami.