Ashlyn Gosa, a senior at Apalachee High School in Georgia, was in class when she said she heard multiple rounds go off outside her door.

Authorities said all teachers at Apalachee High School have an ID wherein they can press a button to alert an "active situation."

The teenager suspected in the shooting at Apalachee High School on Wednesday that left four dead had an apparent affinity for mass shooters, ABC News has learned.

When a gunman opened fire outside Stephanie Reyna's classroom, killing math teacher and football coach Richard Aspinwall, she said her classmates jumped into action.

Four people were killed in a shooting at Apalachee High School on Wednesday.

Colt Gray, the teen accused of opening fire at his Georgia high school, and his father, Colin Gray, both made their first appearances in the same courtroom.

A Georgia community is in mourning after four people were killed in a shooting at Apalachee High School on Wednesday morning, according to authorities.