SAXONBURG — When it comes to preparing for attacks at schools, the worst words that can be said are, “It will never happen here,” according to retired Lt. Col. Dave Grossman.

Grossman, an expert on violence and a former Army Ranger and U.S. Military Academy psychology professor, spoke Wednesday at Cooper Hall on school violence.

His talk was sponsored by the borough.

Grossman said the enemy is “denial.”

“Violence is the most likely thing to kill our students in school,” he said.

Two of the largest juvenile-committed massacres have taken place in Germany, which Grossman noted has some of the strictest gun laws in the world. Others have taken place in other countries with similar laws, such as Norway and Sweden.

“It's not about what's in their hand. It's about what's in their head,” Grossman said.

He said much of this comes from violent movies and video games.

Overall, he said there is no profile of the people who commit these killings. The culprits come from all races and all creeds, and come from different economic and family backgrounds.

However, Grossman said every one of them has dropped out of real life and has immersed himself in violent films and games.

He said the Columbine killers had watched the film “Natural Born Killers” 50 times. Grossman said there was a time when people did not have the technological capability to watch a movie that many times.

And, he said movies and games are getting “sicker” each passing year.

“It's not going away,” Grossman said.

Over his career, he said he predicted school massacres and said he predicted college massacres such as at Virginia Tech. The next thing to happen is workplace and domestic massacres, he said.

Past that, he thinks there will be an increase in day care massacres.

In 2009, he recalled a mass stabbing at a Belgian day care. The attack took place on the anniversary of the death of actor Heath Ledger, who played the Joker in the film “The Dark Knight.” The attacker wore face paint like the Joker and recited a line from the movie before attacking.

Grossman noted that since it was a knife attack, gun laws would not have helped.

In the Sandy Hook school massacre, the attacker broke the glass on the front door of the school and then reached in to open the door.

Grossman said for decades there have been laminated sheets that can cover glass and make the glass shatterproof. It costs about $25 per square foot. The cost of fireproofing a school building can be up to half the construction cost, and adding this technology is a drop in the bucket, he said.

Last year, two parents of Sandy Hook victims sued the school, and one of their points is that there was no laminate on the front door glass.

The children who commit these crimes are “the kids we're raising every day.” Grossman said they watch TV with dinner each day, and watch violent movies while eating snacks.

With certain video games, players get points for killing characters and the play continues.

“This is dysfunctional play. This is pathological play,” Grossman said.

By contrast, play stops in sports and in outdoor play when someone is hurt.

In each case, he said school shooters have immersed themselves in violent forms of media. Not all of these children become killers. Many of those who do not are “the worst bullies in the school,” he said.

Grossman said there are three steps to take to stop these attacks.

n The first is to deter the attackers. By and large, he said the people who commit these attacks are afraid of failure — often they are more afraid of failure than of dying.

He said the best way to deter is to have armed police in schools. Grossman said he cannot find one case of deaths in school attacks when an armed officer is inside the building.

n The second step is to detect. Grossman said the attackers basically are just children, but clues can be found if officials look for them.

He said many potential attackers have been found with “hit” lists or information from the Internet on how to build a bomb.

n The third step is to defeat. This can be done with training and tactical response, but he said the best tool that has saved lives is improved medical technology.

If the technology today was the same as 1970s medicine, Grossman said, the number of people who have died in school massacres would be four times as high.

Along with the obsession with violent media, he said gang violence is exploding.

When he was a boy, Grossman wanted to be like Marshal Matt Dillon from the TV show “Gunsmoke.” Today, he said there are children more inspired by shows like “The Sopranos” and “Breaking Bad.”

“We have flat brainwashed a generation. Mexico is our future,” Grossman said, noting that more people have been killed in cartel violence in Mexico than have died in the wars in Iraq and Afghanistan.

He said violent games have “programmed” children to want to kill police officers. He said “Grand Theft Auto 5” made more money the year it was released than the entire music industry.

Grossman compared the way video games “program” players to the way that training scenarios program officers, though he noted that in training the response often times is not to shoot.

In addition to the domestic threat to schools, Grossman said there is an external threat to schools from terrorists.

He said the most likely place for a 9-11 style attack is at a school, saying that school attacks have happened in countries like Turkey, Algeria, Indonesia and Thailand. In 2009, there were 600 attacks on schools — which he noted were committed by terrorists in their own countries on their own schools.

“You think they won't do it to us?” Grossman asked. “Around the planet, they attack the schools.”

He cited the Beslan school attack in Russia, which was committed in 2005 shortly after Russia pulled out of Afghanistan. There, terrorists blocked exits and forced 1,000 people — almost entirely women and children — into a gym at the school and tortured them by blocking access to water for three days.

On the third day, Russian special operations forces finally broke in. In the end, 314 hostages were killed, with about 200 by a fire that was set in the gym.

Why did it happen in Russia, Grossman asked? He said it could be a dress rehearsal for a similar attack in another country, like the U.S.

“It is our job to take our children and make them as safe as humanly possible,” Grossman said.

In Russia, he noted it took three days for troops to go in. That is because many officers in Russia do not have guns, so they had to wait for a tactical response from the military.

This is common in many countries around the world. However, in the United States, the military cannot act without congressional approval, so Grossman said the police are in charge of these attacks.

Police have to be ready, he said.

“We are at war, and this is the front line of the war,” Grossman said.