A crowd gathers behind police line near the scene of a shooting on December 2, 2015 in San Bernardino, California. One or more gunman opened fire inside a building in San Bernardino in California, with reports of 20 victims at a center that provides services for the disabled. Police were still hunting for the shooter, saying one to three possible suspects were involved. Heavily armed SWAT teams, firefighters and ambulances swarmed the scene, located about an hour east of Los Angeles, as police warned residents away.  AFP PHOTO / FREDERIC J. BROWN / AFP / FREDERIC J. BROWN        (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)
FREDERIC J. BROWN/AFP/AFP/Getty Images
A crowd gathers behind police line near the scene of a shooting on December 2, 2015 in San Bernardino, California. One or more gunman opened fire inside a building in San Bernardino in California, with reports of 20 victims at a center that provides services for the disabled. Police were still hunting for the shooter, saying one to three possible suspects were involved. Heavily armed SWAT teams, firefighters and ambulances swarmed the scene, located about an hour east of Los Angeles, as police warned residents away. AFP PHOTO / FREDERIC J. BROWN / AFP / FREDERIC J. BROWN (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)
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Story highlights

Law enforcement agencies across the country are training civilians how to respond to mass shooter events

The "avoid, deny, defend" training teaches civilians to attack shooters as last resort

2000-2007 saw 7.4 active shooter events per year; from 2008-2013, the number is 16.4

(CNN) —  

A crowd of about 350 listened quietly as the recording of a teacher’s eerie 911 call from Columbine High School bellowed over the church auditorium’s speakers.

“Heads down under the tables! … Oh, God! Kids, just stay down!” a panicked Patty Nielson barked at students taking refuge in the school library, her directives intermittently interrupted by gunfire.

The screen on which the closed-captioned recording was projected later morphed to a dramatization of a Columbine-style attack, as two gun-wielding young men storm through a school throwing chairs aside and shooting students hiding under tables.

Johns Creek police Maj. John Clifton had warned the audience the images might be disturbing.

The group had gathered for a Civilian Response to Active Shooter Events training held at Perimeter Church in the Atlanta suburb, one of several such events increasingly being held around the country. Jackson, Mississippi; Durham, New Hampshire; Greenfield, Indiana; Pampa, Texas; and Orem, Utah, are among the dozens of cities that have staged training sessions of late, and more seem to be popping up every week.

Beverlee Athens, 45, and her husband, John, 59, drove from nearby Alpharetta to attend the Johns Creek event. Katie, 2, bounced on her mother’s lap, oblivious that she was a primary reason her parents were at the church that night.

“I’m not going to sit back and be a victim,” Beverlee Athens said.

John Athens, a retired firefighter and emergency medical services instructor who’s in charge of security at his own church, said he and his wife have concealed-carry permits and “believe in protection,” but the state of the world has him even more vigilant.

“I just know that we’ve got to be prepared. … It’s the day we live in now, unfortunately, and we’ve got her to think about,” he said, nodding to his restless, smiling daughter.

’They do it for fame’

The idea behind CRASE is that the shooters at Columbine, at Virginia Tech, at Fort Hood, at Sandy Hook, in San Bernandino and in scores of other horrific events across the country since the late 1990s aren’t like muggers. They don’t want your wallet or purse.

They want a body count, blood and headlines.

“They’re simply monsters. They do it for fame. They do it for notoriety,” Clifton told the crowd.

U.S. gun violence in graphs, charts

Clifton went on to explain the directives of the CRASE training: avoid, deny, defend – similar to the instructions given to employees January 26 when some kind of shooting event was reported at the Naval Medical Center San Diego. It later turned out to be a false alarm.

“Avoid” means more than run. It’s about knowing where the exits are and visualizing how you’ll get out of a violent situation before one unfolds. Don’t live in fear, but be vigilant, Clifton explained.

“Deny” means taking away a shooter’s chance to kill you, whether it’s by barricading a door, turning out lights, silencing your phone or hiding, preferably behind something that will stop a bullet.

Then there’s “defend,” and that’s where things get tricky, because essentially it means fight. And with a few exceptions, a mass shooter’s targets aren’t soldiers or others who might be trained to fight. They’re regular people: students, coworkers, moviegoers and the like.

“Do not fight fairly. THIS IS ABOUT SURVIVAL,” a handout given to Johns Creek attendees said.

Change in tactics

Pete Blair, executive director for Advanced Law Enforcement Rapid Response Training at Texas State University, which teaches police how to respond to active shooters, says Columbine sounded a “wake-up call.”

Around 2002, realizing the model used by law enforcement officers who responded to the shootings at Columbine was not effective, schools began requesting “avoid, deny, defend” training. CRASE didn’t become formalized until 2013, hence the uptick in training sessions across the nation, he said.

Mother of Columbine killer speaks

More than 85,000 law enforcement officers have been trained in ALERRT operations, and about 5,100 have been trained to be CRASE instructors.

Blair is a self-professed “data-driven guy,” and there are a couple of statistics regarding active shootings that struck him: The first is that in one out of five incidents, it’s the potential victims who stop the shooters; the second is that more than half of active shooter events are over before police arrive, which, on average, takes three minutes.

“That’s a long time for someone to shoot at people,” he said. “It takes some time for the SWAT team to get there, and during that time, the shooter has free rein to keep murdering people.”

Joel Myrick is familiar with fighting an active shooter. A career educator, he was the assistant principal in 1997 at Pearl High School in a Jackson, Mississippi, suburb when a shooting occurred at the school. The event is considered the first in the almost 20-year rash of mass shootings that continues today.

On October 1 of that year, a 16-year-old who had just stabbed and bludgeoned his mother to death drove to the school and killed ex-girlfriend Christina Menefee and classmate Lydia Dew before shooting seven other students, all in the span of a few minutes. Myrick remembers hearing the shots.