After the massacre at Columbine High School, former President Bill Clinton ordered the FBI to investigate and then report the multiple causes of such events. The results are found in " The School Shooter: A Threat Assessment Perspective."

One of the characteristics of school shooters, according to the FBI is a "Fascination with Violence-Filled Entertainment," most importantly video games.

In early April, 1999, I filed a federal wrongful death and product liability lawsuit in Paducah, Kentucky, on behalf of the families of three female students shot and killed by 14-year-old Michael Carneal, who had trained on the most violent video game at the time, "Doom." The next day we appeared on NBC's "Today," and Matt Lauer asked, "What do you fear based upon what you have learned in Paducah?"

"What we fear," I said, "is that other boys in other American high schools would train on the same murder simulator video game and kill more students."

Two weeks later, "Columbine" occurred, the nation learned within 72 hours that Dylan Klebold and Eric Harris had trained on "Doom," even stating in their videotaped suicide note that they wanted to replicate "Doom" in the hallways of Columbine.

Fast forward to 2018 and Parkland, Fla. The Miami Herald reports that Nikolas Cruz played murder simulation video games up to 15 hours a day, just as Adam Lanza of Newton, Connecticut, did before he killed 26 people at Sandy Hook Elementary.

There are neurobiological and structural differences between teen and adult brains. Teens process violent entertainment in the midbrain rather than in the forebrain. The midbrain is the seat of emotion-driven, dangerous copycatting behaviors, and because it is not fully connected to the forebrain, those behaviors are not intercepted. That is why the American Psychological Association, the American Medical Association, and the American Academy of Pediatrics (see editor's note) have all found that violent video games shift the behaviors of all teens who play them toward the aggressive end of the spectrum, with some teens, who are especially at risk, going "Columbine."

In January of this year, the World Health Organization finally found that "video game addiction" exists and that it is a "mental disorder." Indiana University has conducted MRI studies, finding that violent video games actually alter the structures of teen brains.

We are growing Mini-Manchurian Candidates ready, willing, and able to kill. The U.S . military uses violent video games a) to suppress the inhibition to kill of young recruits, and b) to teach killing tactics. Why would anyone think that what works for soldiers would not work for civilian teens? If you want to deny that these games instill the "appetite to kill," that's one thing. But know this: Certain video games teach you tactics that help you kill more victims. One of them was employed by Cruz, the addicted video gamer, when he used smoke bombs in Douglas High in order to draw out and kill more victims.

Is it a good idea to have trained this at-risk ticking time bomb to be a more efficient killer?

What can we do to help keep murder simulation video games out of the hands of teens, especially now that President Trump has correctly identified the causal link between video games and mass killings that all but the video game industry and its flaks know is there?

Here is the simple solution: Each of the states as well as the national government have "Fraudulent and Deceptive Trade Practices Acts" which treat the sale of age-restricted products to underage kids as a "deceptive trade practice" that can be enjoined and punished and thus stopped. Proof of the value of this state and national statutory tool is that in 2012, the attorneys general of forty states entered into consent decrees with 7-Eleven and Circle-K stopping their sale of age-restricted products because those sales constituted a "deceptive trade practice." The sales stopped.

After Columbine, the video game industry and their retailers promised to stop the sale of mature-rated video games to kids under 17, and that it would do so by aggressive age IDing of buyers. They said they would not sell their mature games to kids, but they lied. They have kept doing so.

The Federal Trade Commission with its post-Columbine "secret shopper" stings has proven that millions of units of mature games continue to be sold to kids under 17 with no parents in sight. What is even worse is that the video game industry and its on-line retailers do not check or verify the ages of any video game buyers.

This refusal comes despite the fact that on-line video game sales by BestBuy.com, Amazon.com, Target.com, GameStop.com, WalMart.com, and even ToysRUs.com increased while brick-and-mortar sales have dropped. Age verification for these millions of on-line sales has been available for years, even before Columbine. Just ask the on-line sellers and buyers of alcohol, tobacco, and firearms. The video game industry doesn't want to use this software because it would stop the lucrative sales of mature games to millions of other parents' kids.

The states and the national government should force the video game industry to keep its promises. Its failure to do so poses a public health and safety threat. There is no First Amendment protection for this sham, because the statute we will threaten them with does not turn for its enforcement on the "content" of the games, which the courts have ruled (incorrectly) is protected speech. Rather, they are liable for the deception in telling Congress and the American people that they do not sell these games to kids, when in fact they do, and they know they do. This is fraud.

If the various attorneys general enforce their respective "Fraudulent and Deceptive Trade Practices" statutes, this dangerous game the video game industry plays will be over for the makers of "Grand Theft Auto" and other murder simulators who sell them to our kids. In doing so, they sow the wind and reap the violence whirlwind in Parkland, Fla., and elsewhere.

Jack Thompson is a retired attorney who has labored against the marketing and sale of adult entertainment to children for twenty-one years. His autobiography on this is entitled Out of Harm's Way, published by Tyndale House.

Correction: The original version of this piece refferred erroneously to the American Pediatric Psychiatric Association, which does not exist. The correct reference, to the American Academy of Pediatrics, has been substituted in its place.