Now, some local schools have begun training police, teachers, and even students to respond to active shooters in an entirely new way.
A parent's worst nightmare... developing on the campus of San Jose City College. From one classroom to the next, Joe Hoffar met with little resistance as he opened fire on nearly everyone he saw. But Hoffar is not a deranged gunman and his bullets may leave marks on his victims, but his Airsoft gun is not lethal.
Hoffar is actually a retired Atwater cop and his simulated rampage is part of a fast-growing type of active shooter training called ALICE.
"We're hoping to train students and teachers to survive and if you take that as being heroes, well, maybe so," said San Jose City College Police Chief Ray Aguirre.
Aguirre brought ALICE trainers to campus -- not just for his own staff, but for any police, teachers, nurses -- anyone who sees its value.
ALICE is an acronym for alert, lockdown, inform, counter and evacuate. Most of its concepts have been in practice at U.S. schools since the Columbine massacre in 1999. But trainers from a private company called Response Options say most schools limit their options by instituting lockdown-only responses.
Hoffar's simulated attack came during a practice lockdown.
"And if people are simply cowering under their desks, cowering under a table, thinking that they've locked down, you know, they're sitting ducks," said ALICE trainer Kerry Harris.
Sandy Hook Elementary School, for example, had drilled teachers and students to lock down. 26 of them died in the December shooting. ALICE trainers don't claim their program could've reduced that number, but say it's possible their tools could save lives.
They encourage people to lock down first, barricade themselves and try to avoid the shooter. But as a last resort, they train students and others to launch a counterattack. In one simulated scenario, an active shooter has entered the building and our trainees are prepared to counter. The scale of the counterattack depends on the size of the students.
Harris says a well-trained, well-informed group of college students or even high schoolers has a chance to take control from an active shooter. You could see it happen in one scenario. The counterattack is trickier for younger students, though.
"But a classroom full of kindergarteners can run and scream and throw things in the air and just make themselves a difficult target," Harris said.
Atwater schools are the first in the Valley to institute ALICE training. Two school resource officers attended the San Jose training and they're passing on what they learned to teachers and staff this month.
Students will be next as administrators look to give them every possible safety tool to use when trouble arrives.
"Regardless of how well you prepare, there will be chaos, but hopefully implementing procedures from this ALICE program will help calm the chaos and allow other people to survive," said Atwater police school resource officer Matthew Haywood.
And allow a parent's nightmare to never come true. In Fresno and Clovis Unified, students are trained regularly on lockdowns. Clovis trains staff to counter, but not students.
Neither of the districts criticized ALICE training, but there are some detractors who say they'd rather not see students trained to put themselves in the path of an active shooter.