A few months ago, I posted a review of the harrowing documentary “Do Not Resist.” It includes a scene from a class with Dave Grossman, whose classes on policing and the use of force have become hugely popular in the law enforcement community.

Fittingly, the most chilling scene in the movie doesn’t take place on a city street, or at a protest, or during a drug raid. It takes place in a conference room. It’s from a police training conference with Dave Grossman, one of the most prolific police trainers in the country. Grossman’s classes teach officers to be less hesitant to use lethal force, urge them to be willing to do it more quickly and teach them how to adopt the mentality of a warrior. Jeronimo Yanez, the Minnesota police officer who shot and killed Philando Castile in July, had attended one of Grossman’s classes called “The Bulletproof Warrior” (though that particular class was taught by Grossman’s business partner, Jim Glennon).

In the class recorded for “Do Not Resist,” Grossman at one point tells his students that the sex they have after they kill another human being will be the best sex of their lives. The room chuckles. But he’s clearly serious. “Both partners are very invested in some very intense sex,” he says. “There’s not a whole lot of perks that come with this job. You find one, relax and enjoy it.”

Grossman closes the class with a (literal) chest-pounding motivational speech that climaxes with Grossman telling the officers to find an overpass overlooking the city they serve. He urges them to look down on their city and know that they’ve made the world a better place. He then urges them to grip the overpass railing, lean forward and “let your cape blow in the wind.” The room gives him a standing ovation.

Grossman and Glennon teach the most popular of these classes, but they have competitors. When it comes to teaching cops how to escalate, how to see the world as their enemy and how to find the courage to kill more people, more often, there’s no shortage of options. (The syllabus for one of these courses includes a page of Bible verses relating to when it’s moral and just to kill.) It’s part and parcel with the pseudoscience churned out by William Lewinski at the Force Science Institute in Minnesota, who also preaches that cops should learn to become more lethal (and will testify in court for any cop who takes his advice). I’ve spoken to more than a few sheriffs and police chiefs who want no part of this philosophy, but who also say they can’t really control what their officers do on their own time.

Mother Jones reporter Bryan Schatz recently took one of Grossman’s classes himself.

Marching around the stage in a theater in Lakeport, California, Lt. Colonel Dave Grossman tells his audience that they shouldn’t go out looking for people to kill, because those who need killing—the “gangbangers,” terrorists, and mass murderers—will come to them. All they need to do is be ready. “Are you prepared to kill somebody?” he asks me and the small group of “armed citizens” who’ve paid $90 or more to see him. “If you cannot answer that question, you should not be carrying a gun.”

Two hours into his high-octane, six-hour seminar, the self-described top police trainer in the nation is just getting warmed up. Grossman, a 60-year-old former Army Ranger, wears low-slung blue jeans, an ornate Western belt buckle, and a black button-up emblazoned with the words “Grossman Academy,” the “O” stitched like a bull’s-eye. He sports a military haircut. Onstage are two giant easel pads, their legs taped to the floor so that they don’t go crashing down whenever he hits them to punctuate his points. “We fight violence. What do we fight it with? Superior violence. Righteous violence.” Like a preacher, he doesn’t bother with notes …

Grossman’s worldview makes President Trump sound like Julian Simon.

[Grossman] views the world as almost unrecognizably dangerous: a place where gang members seek to set records for killing cops, where a kid “in every school” is thinking about racking up “a body count.” His latest book, Assassination Generation, insists that violent video games are turning the nation’s youth into mass murderers. The recent wave of “massacres” is just the beginning. (“Please stop calling them mass shootings!”) He smacks the easels: “These [thump] crimes [thump] are [thump] everywhere!” He foresees attacks on school buses and day care centers. “Kindergartners run about point-five miles an hour and get a burst of about 20 yards and then they’re done.” It won’t just happen with guns, but with hammers, axes, hatchets, knives, and swords. His voice jumps an octave: “Hacking and stabbing little kids! You don’t think they’ll attack day cares? It’s already happening in China. When you hear about a day care massacre,” he shouts, “tell them Grossman said it was coming!”

That’s not the end of it. “More people are signing up with ISIS than we can count,” Grossman says. He predicts a terrorist organization will soon detonate a nuclear bomb off the West Coast. “We have never been more likely to be nuked, and we have never been less prepared!” Terrorists will send “suicide bio-bombers” across the border to spread deadly diseases. “The day will come,” Grossman insists. “Folks, it is very, very bad out there!”

This is the guy who has trained more U.S. police officers than anyone else. The guy who, more than anyone else, has instructed cops on what mind-set they should bring to their jobs.

Schatz isn’t the first reporter to attend one of these classes. Bloomberg’s Peter Robison attended one in 2015, taught by Grossman’s colleague Glennon. Here’s a particularly vivid passage from Robison’s account:

Before proceeding, Glennon points to a threat in the back of the room: me. “In 35 years, we have not allowed the press to come into a class,” he says. “The reason is because we don’t trust them.” He says he’s letting me observe because many police chiefs are frustrated no one is advocating for them. They’re tired of being portrayed in the media as racists and unaccountable killers and want a more sympathetic depiction. If my article screws them, he tells the class with a smile, “I’ll fly out to Seattle”—where I live—“and kill him.”

I mean, I’m sure Glennon was joking. (Hilarious!) But in an era in which we have a president who a) is beloved by law enforcement, b) vilifies journalists and c) has expressed his admiration for at least one foreign leader believed to have no qualms about assassinating journalists, that passage is especially disconcerting.

We’re also entering an era in which law enforcement officials appear to be emboldened by Trump’s election. Both the president and Attorney General Jeff Sessions have indicated that federal oversight of local law enforcement is about to end or at least be scaled back considerably. State legislators have followed with bills to hold cops less accountable and allow police agencies to be less transparent after allegations of excessive force. These classes are getting increasingly popular at a time when the dominant political party seems to believe police officers should be given more latitude, get less oversight and not be subject to second-guessing. That seems like a potentially dangerous combination.