Shooting at Centennial, Colo., school

A woman holds her daughter close as parents pick up their children at a church where students from nearby Arapahoe High School were taken after a shooting on the Centennial, Colo., campus.  (Brennan Linsley / Associated Press)

Joanne Kostecka, left, walks with her daughter Dominika Kostecka, 17, from Shepherd of the Hills Church after a school shooting at Arapahoe High School in Centennial, Colo.  (Chris Schneider / Getty Images)

A distraught woman screams as she arrives at a church where students from nearby Arapahoe High School were taken after a shooting on their Centennial, Colo., campus Friday.  (Brennan Linsley / Associated Press)

Law enforcement and fire department vehicles surround Arapahoe High School in Centennial, Colo., where a student with a shotgun wounded two classmates and then apparently took his own life.  (Bob Pearson / EPA)

Students comfort each other at Arapahoe High School in Centennial, Colo., on Friday after a student was shot on campus, apparently by another student. The gunman then killed himself, authorities said.  (Ed Andrieski / Associated Press)

Sheriff’s deputies stand guard over students after they were evacuated to the track and football field at Arapahoe High School in Centennial, Colo.  (Ed Andrieski / Associated Press)