Doorbell camera catches a Bend mother sprinting from her home as word of the school shooting spreads

A home security camera in Bend, Oregon, recorded the moment one mother found out that gunfire had erupted at Silver Rail Elementary School.

What the video shows

The footage, which CNN obtained, shows Gretchen Miller bursting out of her house while shouting that there had been a shooting. She keeps crying "Oh my god" as she races along the street.

Her terror is plain to see in the short clip. It captures a fear that many Bend parents shared that day.

The attack

Authorities say 16-year-old Griffin J. John II opened fire at the school and killed four people. Three of the dead were children.

Kaylub Giamanco shot and killed the teen gunman. That ended the threat.

Two of the victims have been publicly identified so far. They are a 25-year-old teacher along with 5-year-old student Rhoam Summer.

The gunman's background

Investigators say the gun used in the attack was purchased by the shooter's mother, Shauntai May Nickerson. She maintains the teen was a decent boy despite the bloodshed.

John had once attended Silver Rail as a special education student.