At least two people were killed and 18 others were injured, according to police.

A shooter at Marshall County High School in Kentucky opened fire on Tuesday morning, killing at least two people and injuring at least 18 others.

The suspect, a 15-year-old male student, is in custody, and will be charged with murder and assault. Federal, state, and local police are investigating the shooting.

“It is unbelievable that this would happen in a small, close-knit community like Marshall County,” Kentucky Gov. Matt Bevin said in a statement. “As there is still much unknown, I encourage people to love each other.”

This story is still developing. Here’s what we know and don’t know so far.

What we know

The shooter opened fire at Marshall County High School in southwestern Kentucky around 8 am local time on Tuesday, as students gathered at a common area before the day’s first classes.

Two students were killed, according to Kentucky Gov. Matt Bevin. A 15-year-old girl, Bailey Nicole Holt, was killed at the scene, and a 15-year-old boy, Preston Ryan Cope, later died at a hospital, police said.

Eighteen others were injured, police told the Courier-Journal. Fourteen were shot, while four others were injured in other ways as they fled. All the victims are students.

Hundreds of students reportedly fled the school during the shooting, according to Mitchell Garland, a local business owner.

Police apprehended the shooter, the Associated Press reported.

The shooter is a 15-year-old male student, who will be charged with murder and assault, officials said.

The alleged shooter’s identity is so far undisclosed since he’s a juvenile, but it will be made public if the case is successfully moved, as the local prosecutor wants, to adult court and the suspect is indicted by a grand jury.

Police have no reason to suspect anyone else was involved in the shooting, a state detective told the Murray Ledger and Times.

Police said the school is now secure.

The Kentucky shooting is the first fatal school shooting of 2018, according to the AP.

The shooting comes a day after another shooting at a high school in Italy, Texas, where a 16-year-old student shot a 15-year-old girl, who is now recovering from her injuries.

This part of Kentucky has seen school shootings in the past, the AP reported: “Marshall County High School is about 30 minutes from Heath High School in Paducah, Kentucky, where a 1997 mass shooting killed three and injured five.”

So far in 2018, there have been at least 11 school shootings, based on media reports and data from Everytown for Gun Safety, a group that advocates for gun control.

What we don’t know

The shooter’s identity and motive

All the victims’ identities

For more on America’s gun problem, read Vox’s explainer.

Correction: The Associated Press originally reported that two people were killed and 19 others were injured. Instead, 18 others were injured.