Arapahoe High School students outside after shots were reportedly fired.
Map of the area where the reported shooting happened.
Photo from Arapahoe High School
UPDATE: CENTENNIAL, CO - Authorities have identified an 18-year-old as the student who opened fire with a shotgun at a suburban Denver high school before killing himself.
Arapahoe County Sheriff Grayson Robinson identified the shooter Friday night as Karl Halverson Pierson.
The sheriff has said Pierson made no attempt to hide his weapon after entering the school from a parking lot and asking for a teacher by name.
Robinson did not elaborate on any possible motive except to say Pierson had a "confrontation or disagreement" with the teacher.
Authorities now say Pierson shot one fellow student, not two as originally reported. The wounded 15-year-old underwent surgery and was in critical condition.
Another girl who was taken to the hospital with reported minor gunshot wounds, but the sheriff says she was covered in blood from the other student and wasn't injured.
CENTENNIAL, CO - A sheriff says the student who shot at least one other student at a high school near Denver today had been looking for a specific teacher. But that teacher got word of it, and had left the school.
Authorities say a student who confronted the gunman was shot, before the shooter apparently took his own life. The student who was shot was critically injured, and was taken into surgery at a nearby hospital.
A third student was injured at the school, but it's not clear if that student was shot.
It happened at Arapahoe High School in Centennial, about eight miles from Columbine High School in Littleton. That's where two teenage shooters killed 12 classmates and a teacher before killing themselves in 1999.
Police were outside the school after today's gunfire, and students were seen walking toward the running track with their hands in the air.
One woman rushed to the school after getting a text from her daughter saying shots had been fired. She was relieved when the daughter texted that a police officer had entered her classroom and that she was safe.